Tummy Bug Puzzle Unravelled

The bacterium, Helicobacter pylori, which infects the stomach, causes duodenal ulcer disease and is thought to cause stomach cancer. The question of why the bacteria are only found in the stomach has puzzled scientists for many years. Researchers at the Conway Institute and the Children’s Research Centre at Our Lady’s Hospital for Sick Children, Dublin in collaboration with workers at The National Centre for Sensor Research, Dublin City University and The University of Newcastle upon Tyne, UK have discovered the answer and their findings have been published in the current issue of The Proceedings of the National Academy of Sciences.

A family of small proteins called trefoil factors (TFF) are found in the mucous overlying stomach cells. Their job is to protect the stomach cells from harm. A team of researchers led by Dr Marguerite Clyne and Professor Brendan Drumm have now identified that one member of this family (TFF1) acts as a receptor or docking station for the bacteria and helps them to attach to the surface of the stomach. Within the gastrointestinal tract, this receptor is normally found only in the stomach, which would explain why H. pylori only infects the stomach and not the intestine or colon.

The World Health Organisation classifies H. pylori as a class I cancer causing agent. Epidemiological studies carried out by the H. pylori research group at the Conway Institute have shown that infection with the bacteria almost always occurs in early childhood rather than in adult life. Unless treated, it continues to infect the individual throughout their lives causing ulcer disease or cancer of the stomach in some individuals later in life. Gastric cancer is the fourth most common cause of death from cancer in the world.

Professor Drumm and Dr. Clyne, based in the Dept. of Paediatrics, University College Dublin and the Children’s Research Centre, Our Lady’s Hospital for Sick Children, believe TFF1 “to be the most important receptor for H. pylori” even though this family of factors “have never before been considered important in bacterial colonisation”. They will now turn their attention to developing ways of preventing the binding of the bacteria, which they hope will allow them to identify therapeutic targets for the prevention of gastric cancer.