A conditionally pathogenic bacterium produces a cure for intestinal inflammation
A substance produced by a type of symbiotic bacteria in the human intestine may become a new drug for inflammatory bowel diseases such as ulcerative colitis and Crohn's disease, Medical News Today reports.
Researchers from the California Institute of Technology, led by Associate Professor Sarkis K. Mazmanian, found that the bacterium Bacteroides fragilis, which lives in the intestine, produces a substance called polysaccharide A, which provides prevention of inflammation. This bacterium belongs to opportunistic pathogens, i.e., being a common component of the intestinal flora, it can cause disease under certain conditions.
During the experiment, the normal composition of the intestinal flora of mice was disrupted by the introduction of the pathogenic microbe Helicobacter hepaticus, which causes a disease in rodents similar to ulcerative colitis and Crohn's disease in humans. Mice that were additionally injected with Bacteroides fragilis were protected from the disease. The same effect was obtained in animals treated with purified polysaccharide A.
Scientists explain the mechanism of this action by the fact that polysaccharide A stimulates the production by CD4+ lymphocytes (T-helper cells) of the anti-inflammatory protein interleukin-10 (IL-10), also known as cytokine synthesis inhibiting factor (CSIF). Due to this, inflammatory processes in the intestinal wall are suppressed.
According to estimates, about a million Americans suffer from inflammatory bowel diseases, and this number is steadily growing. Thus, the incidence of Crohn's disease in the United States has increased by 400% over the past 20 years.