Umeå researchers find ulcer bacteria in blood

It was shown conclusively in the 1980s that ulcers are caused by the bacterium Helicobacter pylori, a discovery that earned two Australian scientists the Nobel Prize for Medicine in 2005. It is also well established today that a Helicobacter infection is the greatest risk factor for stomach cancer, one of our most common cancer forms.

The adhesion of this bacterium to the mucous lining of the stomach is generally seen as an important first stage in developing symptoms and incipient disease, such as gastritus. To be able to stick to cell surfaces, H. pylori uses so-called adhesive proteins. They are located on the surface of the bacterium and attach to various sugar molecules on the surface of the stomach cells, which provides the bacteria with a firm grip in the turbulent environment of the stomach.

In the article it is now shown that in an infection the bacteria make their way beyond the cell surfaces of the stomach to the underlying blood vessels. Once there, they can also get through the vessel walls and attach to red blood corpuscles. In this way, Helicobacter can transport themselves elsewhere in the body.

Marina Aspholm, the lead author of this work, has also succeeded in showing that H. pylori use the so-called SabA protein in their adhesion to red corpuscles. What’s more, this protein was shown to vary somewhat across Helicobacter bacteria from different patients. This means that the SabA protein is able to adapt to individuals in order to attain the best adhesion.

During an infection, H. pylori can thus adapt its adhesive properties both to the individual stomach lining and to the changes that take place there in the course of a chronic infection and inflammation.