The dangerous causes behind irritable bowel syndrome

 The dangerous causes behind irritable bowel pain

What are the cause of pain in irritable bowel syndrome? It could be a local immune reaction.

Diarrhea and constipation, as well as cramps, are a nuisance for millions of patients with IBS, and patients get worse when doctors ignore these symptoms because they think they are caused by anxiety or fantasies.

"It's all in the mind and between the ears," says Jay Boykstens, a digestive disease specialist at KU Leuven.

But Buikstens sought for many years to understand one of the hallmarks of this syndrome, which is abdominal pain after eating, and he and 40 of his colleagues provided information that supported their hypothesis that the pain was caused by some kind of local allergic reaction to food in the intestine.

"Patients think they have an allergy to something," says Robin Spieler, a digestive disease specialist from the University of Nottingham who was not involved in the study. But testing for a food allergy in the blood does not show any evidence for this, as the idea of a localized immune response in the gut is a new concept.

The first evidence explaining pain appeared 15 years ago when researchers discovered something puzzling in patients with irritable bowel syndrome. "Their immune system was different," says Giovanni Barbara, a digestive disease specialist from the University of Bologna who led the research.

Note that mast cells were activated on biopsies taken from the patients' intestinal tissue. Normally, mast cells play the role of an alarm system in the body, as they release chemicals such as histamine when there is a risk of infection or infection such as infection with parasites, but patients with irritable bowel syndrome do not suffer from any effective infection and this made it strange at first, as the mast cells were not activated Only, they are located unusually close to the nerve endings, causing them to become over-activated.

. "Nobody believed me because doctors and researchers were not convinced that the cause of the pain originated in the intestine," but Boykstens was interested and wanted to know more, as he started with his team because of a common cause of irritable bowel syndrome, which is Intestinal infection caused by acute food poisoning that results in mild illness with few symptoms.

Studies suggest that about 10% of people recover from an intestinal infection as symptoms of irritable bowel syndrome persist. A mild degree of inflammation in the intestine can persist after the infection has ended, leading to chronic pain. But Boykstens had previously examined patients' gut biopsies and found no signs of inflammation, so he postulated a new idea that an intestinal infection inhibits an organ’s ability to tolerate the antigens - protein chains - found in many foods.

During infection, the activity of the immune system increases, and this leads to attacking food antigens as part of the infection, and when this immune reaction continues after its removal, the cause of pain and convulsions after the meal can be explained.

To test this, Buickstens and his colleagues transferred harmful germs to the experimental mice, causing an intestinal infection, and presented them with food containing antigens such as egg white. Egg whites during infection did not have this problem.

With closer examination, the researchers found, after sepsis, that the egg white protein activates a series of reactions similar to what occurs in cases of food allergy. These proteins bind to antibodies called immunoglobulins E IgE that attach to and activate mast cells and then release chemical mediators.

The reaction against the egg white protein lasted four weeks, during which the researchers followed the mice, and the results confirmed the interconnection between mast cells and neighboring intestinal nerves, which Barbara pointed out years ago: “The release of chemical media by mast cells will lead to nerve hypersensitivity and increase their susceptibility to stimulation. This is what the body interprets as pain. ”

"This research leads to the conclusion that the pain associated with Irritable Bowel Syndrome has an organic origin," says Panna Gabry, a specialist in pediatric digestive diseases and mucosal immunity from the University of Chicago. Jabri sought a similar study on celiac disease caused by gluten intolerance, and in 2019 she and colleagues reported that eating gluten causes a severe immune reaction to it, which in turn leads to abdominal symptoms such as pain and nausea.

Buickstens warns that there is a need to differentiate between food allergy and what the mice experienced in this experiment, as the immune response was localized in the intestine only, unlike what people experience when allergic to peanuts or cow's milk, as IgE antibodies circulate in the blood causing general symptoms throughout the body, but blood tests These mice did not show these antibodies.

Is it the same for patients with irritable bowel syndrome?

Boykstens' team tested 12 patients with this syndrome that they were allergic to the most common food allergens such as cow's milk, gluten, wheat, and soy, which were all negative, then the team injected these potential allergens into the patients rectally, and the following tests showed signs of a localized immune reaction to at least one of these substances. The results of the same test on eight healthy volunteers showed the emergence of an intestinal reaction to soy or gluten in two of them, and Boykstens explained why the rest of the individuals were not affected by a mild immune reaction that the intestine tolerated without symptoms.

These results raise many questions, says Daniel Museda, an immunologist from Rockefeller University, as Museda wonders if IgE-mediated local immune reaction also occurs in people with irritable bowel syndrome, is this reaction directed against specific foods, or does it include all of them? And does this reaction appear in all types of the syndrome or not?
Infection-induced plaque is one of these types, as there is irritable bowel syndrome associated with stress, and Buikstens tries to answer this question by experimenting on mice to see if stress can trigger the same reaction in the intestine.

Currently, Irritable Bowel Syndrome is treated only symptomatically, that is, by treating the symptoms in patients due to ignorance of its causes, but if the role of mast cells and IgE antibodies in them is proven, it is possible to respond to immunotherapy directed against it in some cases.