Oneweb's List: Microbiome

• "I might have a different organism on my tongue than you do on your tongue but collectively they bring the same genes to the party - so they are able to perform some of the same functions, for example, breaking down sugars," Dr Birren says.

   

• This finding suggests a shift in thinking from a one-microbe model of disease, that essentially pins the blame for certain illnesses on one bug.

   

• The mysterious microbial world within us is beginning to reveal its secrets

• Published in the journal Nature today, the Japanese study shows that butyrate, a by-product of the digestion of dietary fiber by gut microbes, acts as an epigenetic switch that boosts the immune system by inducing the production of regulatory T cells in the gut.
• Their research demonstrates that butyric acid, a short-chain fatty acid produced by commensal bacteria acts on naïve T cells to promote their differentiation into Treg cells. It achieves this through epigenetic changes that regulate the expression of the genes responsible for differentiation of naïve T cells into Treg cells.

• Here, we show that the mammalian gut contains a rich fungal community that interacts with the immune system through the innate  immune receptor Dectin-1. Mice lacking Dectin-1 exhibited increased susceptibility to chemically induced colitis, which was  the result of altered responses to indigenous fungi. In humans, we identified a polymorphism in the gene for Dectin-1 (CLEC7A) that is strongly linked to a severe form of ulcerative colitis. Together, our findings reveal a eukaryotic fungal community  in the gut (the “mycobiome”) that coexists with bacteria and substantially expands the repertoire of organisms interacting  with the intestinal immune system to influence health and disease.

• University of Calgary researchers reported a 100 percent success rate -- none of the 27 patients who took the tablet-sized pills had a recurrence of C. diff, even though all of them previously had had at least four bouts of the infection. Patients ingested between 24 and 34 capsules containing fecal bacteria, often donated by family members.

   

• In 317 patients treated across 27 case series and reports, IMT was highly effective, showing disease resolution in 92% of cases

• N Engl J Med. 2013 Jan 31;368(5):407-15. doi: 10.1056/NEJMoa1205037. Epub 2013 Jan 16.

• RESULTS:   The study was stopped after an interim analysis. Of 16 patients in the infusion group, 13 (81%) had resolution of C. difficile-associated diarrhea after the first infusion. The 3 remaining patients received a second infusion with feces from a different donor, with resolution in 2 patients. Resolution of C. difficile infection occurred in 4 of 13 patients (31%) receiving vancomycin alone and in 3 of 13 patients (23%) receiving vancomycin with bowel lavage (P<0.001 for both comparisons with the infusion group). No significant differences in adverse events among the three study groups were observed except for mild diarrhea and abdominal cramping in the infusion group on the infusion day. After donor-feces infusion, patients showed increased fecal bacterial diversity, similar to that in healthy donors, with an increase in Bacteroidetes species and clostridium clusters IV and XIVa and a decrease in Proteobacteria species. 

   

• The treatment, now widely employed against recurrent attacks by a nasty intestinal bug known as Clostridium difficile and tested on Crohn’s disease and colitis, is one you’ll likely never see advertised on TV: the fecal microbiota transplant, politely known as the FMT
• Just two months later, the agency relented, saying doctors didn’t need a permit to administer a fecal transplant to patients with recurrent C. diff.

• An ancient remedy

   

  The idea of recolonizing a troubled intestine with someone else’s “good” bacteria is far from new. In The American Journal of Gastroenterology last year, a researcher in China    noted evidence of its use there in the fourth century, for patients near death from food poisoning or severe diarrhea.

1 more annotation...

• Because a fecal transplant is gross, but cramps and bloody diarrhea are aesthetically pleasing?

• Gut Microbiota

  Wed, 13 Nov 13

• The intestinal microbiota has the capacity to synthesize a variety of vitamins involved in myriad aspects of microbial and host metabolism, including cobalamin (vitamin B12), pyridoxal phosphate (active form of vitamin B6), a cofactor in a variety of enzymatic interconversions involved in amino acid metabolism, pantothenic acid (vitamin B5), niacin (vitamin B3), biotin, tetrahydrofolate (generated from dietary forms of folate) and vitamin K. In addition to vitamin B12, gut microbes produce a range of related molecules (corrinoids) with altered ‘lower ligands’ including methyladenine, p-cresol, and other analogs.
• The capacity of the intestinal microbiota to shape immune responses outside of intestine is well documented. Studies have highlighted the ability of the microbiota and specifically SFB to support the development of autoimmune arthritis ⁷⁰ and experimental allergic encephalomyelitis ⁷¹, both of which have been linked to excessive Th17 responses.

• Alterations in intestinal microbiota are associated with obesity and insulin resistance. We studied the effects of infusing intestinal microbiota from lean donors to male recipients with metabolic syndrome on the recipients' microbiota composition and glucose metabolism. Subjects were assigned randomly to groups that were given small intestinal infusions of allogenic or autologous microbiota. Six weeks after infusion of microbiota from lean donors, insulin sensitivity of recipients increased (median rate of glucose disappearance changed from 26.2 to 45.3 μmol/kg/min; P < .05) along with levels of butyrate-producing intestinal microbiota. Intestinal microbiota might be developed as therapeutic agents to increase insulin sensitivity in humans; www.trialregister.nl; registered at the Dutch Trial Register (NTR1776).