Dr. Mutlu explains how inflammatory bowel disease is affected by good and bad bacteria.
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We think good and bad bacteria contribute a lot to inflammatory bowel disease. There are several lines of evidence that suggest that in our literature. First of all, when you look at animals which are genetically altered to get colitis, which is similar to inflammatory bowel disease in humans, if you place that animal in a bubble where there are no microbes or bacteria, or anything for that matter, those animals rarely, if at all, get colitis. When you take them out of this bubble environment, which is completely germ-free, and expose them to a regular cage where mice and rats are kept in a research laboratory, they start developing colitis. There is strong evidence, therefore, that at least in animals, bacteria play a significant role in the initiation or progression of the disease because they seem to be required to induce the disease in almost all models of colitis that mimics inflammatory bowel disease. In humans, we also have evidence of, evidence that bacteria play an important role in inflammatory bowel disease pathogenesis. For example, when we do an ileostomy in a patient with Crohn’s disease, which means we create a bag of the small intestine, the small intestine opens up to the abdomen and it is hooked to a bag where stool is drained. It causes the disease to go into remission for extended and prolonged periods of time. That means we are actually diverting the patient’s stool stream away from their colon where numerous bacteria are present, and when we divert it away, the disease seems to get better. Similarly, when we look at the areas where, for example, Crohn’s disease occurs as well as ulcerative colitis occurs, these areas tend to be at the areas where the counts of bacteria are at their highest. For example, the cecal area, or the ileocecal area, I should say, there is an ileocecal valve there that increases the numbers of bacteria. Additionally, the rectum, which is a major site for ulcerative colitis as well as Crohn’s disease, have some of the highest counts of bacteria within the entire GI tract. So we think that good and bad bacteria probably play a significant role. Unfortunately, there has been many experiments looking for a single bacteria or a single organism that causes inflammatory bowel disease, but that has not been found yet, and even the ones that have been implicated have not been implicated in majority of the studies. There are many negative as well as positive studies. So most researchers, including myself, we think that this disease probably comes from a set of microorganisms, including bacteria. There could be other organisms such as yeasts, such as viruses, and other organisms that we’re not completely aware of that may be associated with the disease, and it may not be a single organism but maybe a group of organisms that are either deficient or that are too much in number in patients with inflammatory bowel disease.