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Showing results for tags 'bacteria'.
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Celiac.com 10/13/2011 - While certain immunologic risk factors have been identified for celiac disease, it is still unclear why some develop the disease and others do not. One possibility is that some people are more able to digest gluten than others. Those who cannot break down the gluten into smaller proteins higher in the digestive tract, in the mouth and stomach, could develop an immune reaction to the full, unaltered protein. Maram Zamakhchari and other researchers at Boston University and collaborating sites investigated whether bacteria present in the mouth can play a role in breaking down gluten. The authors reported in the journal PLoS ONE, published by the Public Library of Science, that two bacterial species present in the normal oral flora were able to degrade gluten. The species are Rothia mucilaginosa and Rothia aeria, as the authors reported in the online version of the publication on September 21, 2011. This finding raises the question of whether people with celiac disease have different levels of these bacteria than those without celiac disease. The species R. mucilaginosa is found in the mouth and the intestines while R. aeria is only found in the mouth. The authors attempted to answer this question by looking at saved intestinal biopsy specimens from patients with and without celiac disease. They found no difference in the presence of the intestinal bacteria between celiacs and healthy patients. This study supports the idea that bacteria in the digestive tract may play a role in the development of celiac disease. While there was no difference in gluten-digesting bacteria in the intestines of celiac patients, the study did not evaluate the bacteria levels in the mouth. Patients with celiac disease have an increased incidence of Sjogren's syndrome, which features decreased mouth saliva, and suggests that oral digestion could be related to developing celiac disease. Assessing the presence of these bacteria in the mouths of celiacs versus the general population will be an important next step in the research. Source: Identification of Rothia Bacteria as Gluten-Degrading Natural Colonizers of the Upper Gastro-Intestinal Tract. PLoS ONE 6(9): e24455. doi:10.1371/journal.pone.0024455
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Celiac.com 03/15/2011 - For celiacs, it's not really the cinnamon bun that's the enemy. Nor the pizza crust, nor the ravioli. It's the gliadin in these foods - the alcohol-soluble portion of the gluten protein - that's the real culprit. Gliadin is the "gladiator" of the human digestive tract. When we ingest gliadin, enzymes try to break it down into a form that can be absorbed by the small intestine. But gliadin resists, fighting hard to remain intact. A regular small intestine has, like any good fortress, a protective wall: the mucosal lining of the intestine. This layer of mucus normally acts as a barrier against gliadin's assaults. But in a celiac intestine, the mucosal lining is permeable. With gliadin's destructive power enhanced by its enzyme sidekick, tissue Transglutaminase (tTG), it quickly gets past this poorly-guarded layer. Scientists are working to put their finger on exactly what makes the mucosal lining of a celiac's small intestine so permeable. Now a January study by Czech researchers found at least one thing that affects the permeability of the intestinal mucosa: gut bacteria. In this study, called "Role of Intestinal Bacteria in Gliadin-Induced Changes in Intestinal Mucosa: Study in Germ-Free Rats", researchers tied off sections of rats' intestines and introduced various kinds of bacteria to each section. They wanted to measure the effect that these bacteria had on the intestinal mucus - or more specifically, on the goblet cells that produce the intestinal mucus. To ensure that the kinds of bacteria in the rats' intestines were under experimental control, the rats had been raised from birth in germ-free conditions. They found that introducing gliadin to the intestines had the effect of decreasing the mucus-producing cells, thereby eroding the intestines' protective layer. No big surprises there - gliadin is a fighter, a digestive "gladiator", after all. But when they added strains of so-called harmful bacteria, Escherichia coli (otherwise known as E coli) or Shigella, the mucus-producing cells decreased even more. The cells first secreted massive amounts of mucus, then promptly exhausted themselves and gave up. This left the intestine looking very similar to that of a person in the early stages of celiac disease, say the researchers. But the tale did indeed have a happy ending. Along came the good bacteria, Bifidobacterium bifidum (or "Biff" for short). The mucus-producing cells in the small intestine increased when Biff was present. In fact, Biff was able to partially reverse the mucus-decreasing effects of E coli and Shigella. The researchers concluded that the composition of gut bacteria has an effect on the protective mucus of the intestines: an overgrowth of bad bacteria decreases the protective layer, while the addition of good bacteria increases the protective layer. Their study may eventually lead to treatment options for human celiacs, by finding ways to protect tender intestines from the harmful effects of gliadin. Source: PLoS One. 2011 Jan 13;6(1):e16169
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Celiac,com 10/08/2010 - Many people are familiar with probiotics, such as acidophilus, Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus case, which promote beneficial gut bacteria, and are commonly found in yogurt, kefir and other fermented milk products. But how many of us have heard of polysaccharides, which are a particular kind of carbohydrate made up of of a number of monosaccharides joined together by something called glycosidic bonds. On a simpler note, polysaccharides are also known as pre-biotics, because they serve as fuel for probiotic bacteria, and help to promote healthy ratios of beneficial bacteria to non-beneficial bacteria in the gut. It is well-known among scientists that diet has a major influence on the health and diversity of gut microbiota. People with celiac disease must follow a gluten-free diet in order to avoid associated damage and health disorders. When people with celiac disease follow a gluten-free diet, their celiac symptoms disappear and their gut begins to heal itself from the damage. The health effects of the diet for people with celiac disease are overwhelmingly positive. However, there is some evidence that by eliminating gluten, people with celiac disease are making themselves susceptible to a plunge in beneficial gut bacteria, and an elevated ratio of bad-to-good gut bacteria. This may have immune-system implications for those people. To test this hypothesis, a team of scientists recently conducted a preliminary study to determine if a gluten-free diet alone could change the make-up and immune properties of gut microbiota. The team included G. De Palma, I. Nadal, M. C. Collado, and Y. Sanz. Their full results appear in theSeptember, 2009 issue of the British Journal of Nutrition. To briefly summarize their study, the team enrolled ten healthy individuals without celiac disease, averaging just over 30 years of age. They put these people on a gluten-free diet for a month. Subsequent analysis of fecal microbiota and dietary intake showed a decrease in healthy gut bacteria, coupled with an increase of unhealthy bacteria that corresponded with reduced intake of polysaccharides after following the gluten-free diet. Another healthy control group that ate a diet that contained gluten, and thus provided polysaccharides. In addition representing an adversely change in gut microbiota, the samples taken while the individuals followed a gluten-free diet also exerted reduced immune stimulatory effects on peripheral blood mononuclear cells than those of subjects on a regular gluten-containing, polysaccharide-rich diet. Should these findings be confirmed by subsequent studies, the results could call attention to a more comprehensive approach to proper dietary intake in people with celiac disease, including dietary counseling, and possible supplementation of the diet with polysaccharides. Source: Br J Nutr. 2009 Oct;102(8):1154-60.
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Celiac.com 03/19/2010 - Celiac disease is a chronic inflammatory disorder of the gut triggered by an adverse immune response to dietary gluten proteins in genetically susceptible individuals. One of the first ways the body responds to offending proteins in an adverse celiac disease response is by producing mucous via IgA secretion in an effort to neutralize offending antigens and pathogens. A team of researchers recently sought to better document the relationships between immunoglobulin-coated bacteria and bacterial composition in feces of celiac disease patients, untreated and treated with a gluten-free diet (GFD) and healthy controls. The research team included Giada De Palma, Inmaculada Nadal, Marcela Medina, Ester Donat, Carmen Ribes-Koninckx, Miguel Calabuig, and Yolanda Sanz. They observed that intestinal dysbiosis and reduced immunoglobulin-coated bacteria are associated with celiac disease in children. Both untreated and treated celiac disease patients showed markedly lower levels of IgA, IgG and IgM-coated fecal bacteria compared to healthy controls. Celiac disease patients showed substantially reduced ratio of Gram-positive to Gram-negative bacteria compared to control subjects. Untreated celiac disease patients showed less abundant group proportions (P<0.050) of Bifidobacterium, Clostridium histolyticum, C. lituseburense and Faecalibacterium prausnitzii than did healthy controls. Untreated celiac disease patients showed more abundant group proportions (P<0.050) of Bacteroides-Prevotella than in control subjects. Both untreated and treated celiac disease patients showed significantly impoverished (P<0.050) levels of IgA coating the Bacteroides-Prevotella compared with healthy controls. From these results, the research team concluded that intestinal dysbiosis plays a role in reduced IgA-coating bacteria in celiac disease patients. This offers a fresh perspective into the possible relationships between the gut microbiota and the host defenses in celiac disease patients. Source: BMC Microbiology 2010, 24 February
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Research indicates that rod-shaped bacteria, of the species Clostridium, Prevotella, and Actinomyces, in the proximal small intestine may contribute to some cases of celiac disease in children. Recent data builds on previous research by the team from 1985 to 1996, which proved that rod-shaped bacteria were present in the proximal small intestine of Swedish children with celiac disease, but not in those without celiac disease. For the current study, Sten Hammarström and colleagues from Umeå University in Sweden used an electron microscope to scan proximal small intestine biopsies from 45 children with celiac disease taken between 2004 and 2007, and 18 without the condition. To identify the bacteria, they used 16S ribosomal DNA sequencing in DNA extracted from biopsies washed with solution containing an agent that enriches bacteria attached to the epithelial lining. In healthy children with no celiac disease, Streptococcus and Neisseria bacteria are most common of the normal, mucosa-associated microbial flora of the proximal small intestine, along with a limited number of other genera, including Veillonella, Gemella, Actinomyces, Rothia, and Hemophilus. Surprisingly, the researchers found that microbial flora of the proximal small intestine in biopsies from celiac disease patients differed only slightly from that of the control subjects. Only a single biopsy tested positive for rod-shaped bacteria. This finding made the team to look more closely at the microbial flora of nine frozen celiac disease samples that showed the presence of rod-shaped bacteria. In these samples, microbial flora were substantially richer in Clostridium, Prevotella, and Actinomyces compared with biopsies lacking rod-shaped bacteria. The researchers also note that all three types of bacteria could be found in two current celiac disease biopsies taken from children born during the celiac disease epidemic in Sweden in 1985–1996, when the earlier study was carried out. During this time, rates of celiac disease in children younger than 2 years of age increased four-fold. “We hypothesize that the increased frequency of rod-shaped bacteria in the jejuna mucosa of celiac disease children at least partly was due to the changes in infant-feeding practice during that time,” write the researchers. The changes resulted from new national feeding recommendations for infants to delay the introduction of gluten-containing foods from 4 to 6 months. This meant that many more children consumed their first gluten without the protective benefits of breastfeeding, the researchers write. The recommendation was later reversed. The study by Hammarström and co-workers supports their conclusion that these rod-shaped bacteria may contribute to celiac disease in genetically susceptible individuals by uptaking and transforming gluten into large immunogenic peptides, which can then cross with the bacterium through the epithelium, or interfere with the barrier action of the epithelium to permit the passage of gluten into the under-laying tissue. “Such bacteria could be seen as an adjuvant promoting T-cell activation,” they say. “Whether the identified bacteria have any of these properties remain to be elucidated.” Am J Gastroenterol 2009; 104: 3058–3067
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Celiac.com 06/09/2009 - Results of a recent small population study done in Spain suggest that a gluten-free diet may change gut bacteria balance by decreasing beneficial bacteria and increasing detrimental bacteria. Certainly, gut health is an issue to most people with celiac disease. Recent studies suggest that people with celiac disease benefit from bifidium and lactobaccilus supplements, so it's possible that such benefit is in part an offsetting of damage due to gluten-free diet; at least, a connection seems possible. The Spanish study follows just ten individuals for just one month on gluten-free diets. A large-scale, long-term study might make very different observations, and reach very different conclusions. The study found no significant differences in dietary intake before and after the gluten-free diet except for reductions (P=0.001) in polysaccharides. Bifidobacterium, Clostridium lituseburense and Faecalibacterium prausnitzii proportions decreased (P=0.007, P=0.031 and P=0.009, respectively) as a result of the GFD analysed by fluorescence in situ hybridisation (FISH). Bifidobacterium, Lactobacillus and Bifidobacterium longum counts decreased (P=0.020, P=0.001 and P=0.017, respectively), while Enterobacteriaceae and Escherichia coli counts increased (P=0.005 and P=0.003) after the GFD assessed by quantitative PCR (qPCR). TNF-alpha, interferon-gamma, IL-10 and IL-8 production by PBMC stimulated with faecal samples was also reduced (P=0.021, P=0.037, P=0.002 and P=0.007, respectively) after the diet. The study doesn't provide any real evidence to support a conclusion one way or the other, especially their conclusion that a gluten-free diet "may constitute an environmental variable to be considered in treated Coeliac disease patients for its possible effects on gut health." The fact is that beneficial, probiotic bacteria in the human gut are influenced by diet. The more fruits, vegetables, and high fiber foods we consume, the healthier our bacteria will be. The Spanish study makes no mention of the subjects' diets. Were they fed high fiber, low fat diets rich in fruits and vegetables, or did they eat a standard western diet with no gluten? It would be interesting to compare the gut bacteria levels of people before celiac disease diagnosis and after celiac disease diagnosis to see if a gluten-free diet improves gut bacteria overall, or if the Spanish results would be seen again. Br J Nutr. 2009 May 18:1-7.
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Celiac.com 06/19/08 - Today in most modern countries, children are being raised in bacteria-free environments, yet studies are seeing a rising incidence of autoimmune disease and allergies. Previous studies have found that Finnish children are six times more likely to have type 1 diabetes and a five times higher rate of celiac disease than Russian children despite equal genetic susceptibility. Over-cleanliness and life-style may be promoting the higher prevalence of these disorders. The Diabimmune study, backed by the EU with EUR 6 million in financing, is asking whether by removing all bacteria, we are not actually weakening our children's immune systems. Led by the University of Helsinki, researchers from 5 European countries will collaborate on Diabimmune, a study involving some 7000 children which will last from 2008-2013. The study will focus on the development of the intestinal bacterial flora after birth, the effect that the living environment has on the composition of the bacterial flora, the effect infections have on the maturation of the human immune system, and the operation of the white blood cells that regulate immune responses. In addition, the researchers will examine whether the protection conferred by infections against autoimmune and allergic responses is associated with the overall infection load or due to specific microbes. It is expected that the results will provide much needed insight into celiac disease, other autoimmune disorders, and allergies. For the first time, researchers will comprehensively monitor the composition of microbes populating the intestines of developing infants and study how the microbes may influence the development of allergies and autoimmune disease, including celiac disease. Finally, conclusive evidence may be found which may answer the question of whether gut bacteria is involved the pathogenesis of celiac disease. Are immune systems becoming lazy? European Research Headlines 18 June 2008 http://ec.europa.eu/research/headlines/news/article_08_06_18_en.html Researchers from five countries to test hygiene hypothesis with EU funding University of Helsinki 29 May 2008 http://www.med.helsinki.fi/english/news/20080529_DIABIMMUNE.htm
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Am J Gastroenterol. 2004 May;99(5):894-904 Celiac.com 06/08/2004 – To determine what triggers celiac disease, researchers recently used an electron microscope to look at the jejunal biopsies of several groups of children: A group with untreated celiac disease, one with treated celiac disease, another with challenged celiac disease, and a healthy control group. The researchers discovered rod-shaped bacteria attached to the small intestinal epithelium in both the treated and untreated celiac-disease groups, but not in the healthy control group. The researchers conclude: "Unique carbohydrate structures of the glycocalyx/mucous layer are likely discriminating features of celiac disease patients. These glycosylation differences could facilitate bacterial adhesion. Ectopic production of MUC2, HD-5, and lysozyme in active celiac disease is compatible with goblet and Paneth cell metaplasia induced by high interferon-gamma production by intraepithelial lymphocytes." The idea that bacteria may be involved in the pathogenesis of celiac disease is a hypothesis that was also proposed by Roy S. Jamron in an article that originally appeared in the Spring 2004 edition of Celiac.coms Scott-Free Newsletter, which is further supported by this research.
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