JACKSONVILLE, Fla. -- As many as one in four people in westernized countries experience pain or discomfort in their upper abdomen, and physicians have almost nothing to offer except anti-acid medicines, which usually don't work. Now, in a small but novel study, researchers have found evidence that an abnormal amount of inflammatory cells populates the upper intestine of affected individuals, which suggests a fresh way of understanding the common complaint.
The study, published in the September issue of Clinical Gastroenterology and Hepatology and conducted by researchers in the U.S., Sweden, England, and Australia, may also point to innovative methods to treat the condition and eliminate discomfort.
"Newly-designed, targeted anti-inflammatory medicine aimed at blocking the function of these cells might be very useful, if our results are validated," says the study's lead researcher, Nicholas J. Talley, M.D., Chair of Internal Medicine at Mayo Clinic in Jacksonville.
"We are quite intrigued by what we have discovered, because it probably represents a new disease entity, one that might be capable of diagnosis and management," Dr. Talley says.
The scientists don't know why inflammatory cells are present in one particular region of the small intestine, the duodenum that connects to the stomach, but they theorize that it could result from an allergic reaction to certain foods. Patients examined did not have infections, celiac disease (an autoimmune reaction to gluten protein), or cancer.
"I believe food intolerance can lead to motor and sensory abnormalities that are perceived as pain and discomfort," Dr. Talley says. "But we have no evidence yet that this is definitely the case."
To conduct the study, researchers in Sweden offered endoscopic examinations to 51 Swedish participants who complained of "nonulcer dyspepsia" as well as 49 randomly selected participants who had no pain. Dyspepsia is chronic or recurrent pain, or a feeling of abdominal fullness after eating or nausea, and the nonulcer form means there is not any structural abnormality such as an ulcer. For reasons that are not clear, sensitivity to stomach acid occurs in some of these patients, but acid suppression therapy does not work in two-thirds of patients who try it. There are really very few effective therapies, Dr. Talley says.
During the endoscopy procedure, physicians removed biopsy tissue from several places in the small intestine of participants, and the samples were examined by pathologists who did not know who the samples belonged to.
The researchers found significantly more eosinophil cells in people with nonulcer dyspepsia, compared to the control group population, but these cells were found only in the duodenum, the place in the intestine where most chemical digestion takes place. Eosinophils are white blood cells, part of the immune system, which fight parasites.
The researchers cannot yet say whether duodenal esoinophilia is the cause of the pain or an effect of another factor causing the disorder, although Dr. Talley says "a casual link remains our hypothesis.
"The presence of these cells has been overlooked because no one has used rigorous quantification methods before, and because biopsy examinations of the duodenum are not routinely performed," he says. "Now we have a new direction to go in."
The study was funded in part by Swedish grants, the University of Sydney, and Astra Zeneca Inc.