Other stomach microbiota modulate resistance to H. pylori-driven ulcers

Mice with different naturally occurring stomach bacteria have distinct susceptibilities to disease caused by Helicobacter pylori, the well-known cause of ulcers in humans, according to a study published online ahead of print in the journal Infection and Immunity. This is the first study to document (in mice) that the presence of certain bacteria in the stomach microbiota can prevent pathology from H. pylori.

The gastro-intestinal tract is a veritable ecosystem packed with microbes, and over the last decade, investigators have been discovering that the species composition of that ecosystem can have a profound effect on human health. But the eureka moment that led to this study came "when we realized that mice from different vendors mount different responses to H. pylori infection," says principal investigator Karen Ottemann of the University of California, Santa Cruz.

Following this discovery, the researchers divided mice from the vendor, Taconic Farms, into three groups: mice treated with antibiotics in order to kill some of the resident bacteria, mice that were fed normal stomach bacteria after antibiotic treatment, and mice that were not treated. They then infected each group with H. pylori, and assayed the animals' stomachs for .

"The antibiotic-treated mice had small quantities of particular , called Th1 T helper cells," says Ottemann. Both the untreated mice, and the treated mice that were then fed normal had normal (higher) levels of Th1 T . These results suggested that the normal stomach microbes contribute to disease caused by H. pylori, says Ottemann.

The researchers then determined that around 4,000 were different in the high- and low-inflammation (no antibiotics, and antibiotic-treated, respectively) mice. Notably, the mice with low inflammation "had elevated amounts of Clostridia, bacteria known to prevent inflammation in the intestine," says Ottemann. Thus, the Clostridia may be key to dampening H. pylori pathology, although that remains to be determined, she says.

Ottemann says that this research may lead to predicting future H. pylori disease, including ulcers and gastric cancer—which has few treatment options and high mortality—based on stomach .

"After we determine which microbes underlie H. pylori disease outcomes, we could test whether H. pylori-infected people harbor those particular bacteria, and target them for curing," says Ottemann. Alternatively, such people could receive the protective bacteria as probiotics. The latter might be a superior option, because while prone to ulcers in middle and advanced age, people who harbor H. pylori are less likely to get esophageal cancer and asthma.

More information: A.S. Rolig, C. Cech, E. Ahler, J.E. Carter, and K.M. Ottemann, 2013. The degree of Helicobacter pylori inflammation is manipulated by the pre-infection host microbiota. Infect. Immun. Online ahead of print 19 February 2013, doi:10.1128/IAI.00044-13

Related Stories

Going from ulcers to cancer

Aug 22, 2008

Researchers have uncovered a big clue as to why some of the bacteria that cause stomach ulcers pose a greater risk for serious problems like stomach cancer than others; it turns out these bacteria can exploit the surrounding ...

Recommended for you

Could trophoblasts be the immune cells of pregnancy?

Dec 18, 2014

Trophoblasts, cells that form an outer layer around a fertilized egg and develop into the major part of the placenta, have now been shown to respond to inflammatory danger signals, researchers from Norwegian University of ...

Moms of food-allergic kids need dietician's support

Dec 18, 2014

Discovering your child has a severe food allergy can be a terrible shock. Even more stressful can be determining what foods your child can and cannot eat, and constructing a new diet which might eliminate entire categories ...

Multiple allergic reactions traced to single protein

Dec 17, 2014

Johns Hopkins and University of Alberta researchers have identified a single protein as the root of painful and dangerous allergic reactions to a range of medications and other substances. If a new drug can ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.