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PET tests new treatment for irritable bowel
Study using scans to determine if patients reduce symptoms with cognitive therapy
By LOIS BAKER
Contributing Editor
Can people with irritable bowel syndrome (IBS) reduce their symptoms by learning to alter the brain's processing of pain signals?
Researchers at UB and the Buffalo Veterans Affairs Medical Center (VAMC) think the answer is "yes."
IBS is a common gastrointestinal condition characterized by recurrent abdominal pain and abnormal bowel movements. It afflicts 25-35 million people in the United States, accounts for 2.4-3.5 million doctor visits annually, and can have a devastating impact on quality of life. There is no standard medical treatment.
Jeffrey Lackner, assistant professor of medicine and director of UB's Behavioral Medicine Clinic, is conducting a $2 million, four-year, multi-site trial funded by the National Institutes of Health to test the effectiveness of a non-drug psychological treatment—cognitive therapy—in relieving IBS symptoms.
In a new arm of that study, UB researchers will use positron emission tomography (PET) scanning to determine if the improvements reported by IBS patients who undergo cognitive therapy correspond with objective changes in brain activity that processes pain stimuli. The study is the first to use PET scanning to study this aspect of IBS.
PET is a useful tool for this study because it visualizes physiological processes in real time. Scientists believe IBS symptoms are due to hypersensitive nerves that misfire pain signals to brain regions that register pain sensations. Research has shown that these pain signals—triggered by intestinal contractions, stress, hormonal changes, food and bloating—activate a different pattern of brain activity in people with IBS than in individuals without IBS.
These findings suggest that IBS involves "faulty wiring" of nerves connecting the gastrointestinal tract and the brain. Lackner and colleagues hypothesize that cognitive therapy, which teaches patients to identify and correct tension-inducing beliefs that aggravate their symptoms, will enable patients to decrease their IBS pain by dampening the activity of brain structures involved in processing pain signals.
The PET study will involve 10 IBS patients and 10 healthy controls. Lackner is collaborating with Alan Lockwood, professor of neurology and director of the UB-VAMC PET Center. Brain scans will be taken before and after the participants with IBS complete a 10-week cognitive therapy treatment program. During the scans, participants will undergo a bowel stimulus, which involves placing a balloon catheter in the lower large intestine (colon). A computerized pump will inflate the balloon to specific pressure levels, which can be moderately uncomfortable, for a short time to simulate abdominal discomfort.
The researchers then will compare brain activity in IBS patients, before and after therapy, with that of healthy volunteers. The PET scans produce real-time images of blood flow to the brain's pain centers, which can show whether the therapy has been successful in rewiring the pain circuits
Additional researchers on the study are Thomas Mahl, associate professor of clinical medicine, and Leonard Katz, professor emeritus of medicine.
A UB Interdisciplinary Research and Creative Funds Award supports this arm of the IBS study.