Irritable bowel: Scientists identify the mechanism that causes the development of irritable bowel syndrome
These clinical studies have highlighted the existence of a mechanism that links certain foods to the activation of cells that release histamine in pain and discomfort.
In Belgium, KU Leuven researchers have identified the biological mechanism that explains why some people experience abdominal pain when they eat certain foods. This discovery paves the way for more effective treatment of irritable bowel syndrome. The study, conducted in mice and humans, was published in the scientific journal Nature.
A real disease
For some patients, gluten-free diets provide some relief, but why it works remains a mystery. "Very often, doctors do not take these patients seriously, and the lack of an allergic response is used as an argument that it is all in the mind and that they have no problem with intestinal physiology," explains Professor Guy Boeckxstaens , a KU Leuven gastroenterologist and lead author of the new research. Before continuing: "With this new knowledge, we provide more evidence that we are facing a real disease."
These clinical studies reveal that there is a mechanism that links certain foods to the activation of cells that release histamine in pain and discomfort. In the past, previous research had shown that blocking histamine, an important component of the immune system, had improved the condition of people with irritable bowel syndrome. During this study, the medical team wanted to find out why the immune system could no longer tolerate certain foods.
Often times, patients notice the onset of symptoms after a gastrointestinal infection, so the researchers began with the idea that an infection while a particular food is present in the gut could sensitize the immune system to that food.
A reaction to ovalbumin
To test this hypothesis, the researchers infected mice with a stomach virus and fed them ovalbumin, a protein found in egg white. Once the infection cleared, the mice were given ovalbumin again to see if their immune systems were sensitized. Thus, the researchers found that ovalbumin caused mast cell activation, histamine release and digestive intolerance with increased abdominal pain.
The researchers then checked whether people with irritable bowel syndrome reacted in the same way. When IBS-associated dietary antigens (gluten, wheat, soy, and cows milk) were injected into the intestinal wall of 12 patients, localized immune responses similar to those seen in mice occurred. No reaction was observed in healthy volunteers.
"This is further proof that the mechanism we unraveled has clinical relevance. But knowing the mechanism that leads to mast cell activation is crucial and will lead to new therapies for these patients," said Professor Boeckxstaens. Other studies carried out on a larger panel of participants have yet to confirm these results.