The researchers found fewer Bacteroides bacteria in the mice, but higher levels of Clostridia bacteria, which regulate anti-inflammatory responses. Significantly, many inflammatory bowel disease symptoms subsided, such as bleeding and ulceration of the small intestine.
People living in relatively hygienic environments are not regularly exposed to parasitic infections, such as worm infections. Research has found that this could lead to some people being more susceptible to inflammatory bowel disease. The Nod2 gene codes for a protein involved in stimulating an immune response against harmful bacteria. Its mutation is associated with inflammatory bowel disease in some people. Researchers study the disease by designing mice lacking this gene. These mice have a compromised mucus layer in their small intestines, leading to colonization by a harmful bacterial called Bacteroides and symptoms similar to inflammatory bowel disease. Parasitologist Yvonne Lim of Malaysia’s University of Malaya and colleagues in the United States infected mice lacking the Nod2 gene with common parasitic worms called helminths. They then measured the amount and types of bacteria in their intestines and stools. They found fewer Bacteroides bacteria in the mice, but higher levels of Clostridia bacteria, which regulate anti-inflammatory responses. Significantly, many inflammatory bowel disease symptoms subsided, such as bleeding and ulceration of the small intestine. The team also found that members of a rural indigenous tribe in Malaysia, who have a high prevalence of worm infection and a low prevalence of inflammatory bowel disease, had fewer harmful Bacteroides bacteria in their small intestines than Malaysians living in the capital city Kuala Lumpur. Treating the tribe members for the parasitic worm infection led to an increase in Bacteroides and a corresponding decrease in Clostridia. This suggests that the existence of parasitic worms triggers growth in Clostridia, which might either outcompete Bacteroides for resources they need for survival, or release toxins that kill them. Either way, it appears that worms help prevent inflammatory bowel disease. “This study is unique in that it highlights the potential benefit of low levels of worm infections,” says Lim. The team next plans to investigate the mechanisms that allow Clostridia to outcompete Bacteroides, and explore the use of worm infections, along with probiotic bacteria, in the treatment of inflammatory diseases. Further information Professor Yvonne Ai-Lian Lim E-mail: [email protected] Faculty of Medicine University of Malaya ---------------------------------------------------- Asia Research News is our annual magazine to highlight exciting research studies from our partners. 25,000 copies are printed and distributed to key figures in research. Download a PDF copy from the link below or contact us if you would like print copies.
