Articles about new Irritable Bowel Syndrome drugs, treatment methods, research etc

Effectiveness Of Serotonin And Nerve Stimulants On Irritable Bowel Syndromes Assessed By Studies

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22 May 2007

Studies have shown that gastrointestinal (GI) tract function is often influenced by specific stimulants or reactors, which sometimes cause irritable bowel syndrome (IBS) or constipation. Two studies presented at Digestive Disease Week 2007 (DDW) take a closer look at GI stimulation, including one examining the role of serotonin and reactions to certain types of foods and another looking at the potential therapeutic value of nerve stimulation for constipation. DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"We know that conditions of the bowel, such as constipation, diarrhea and irritable bowel syndrome, are quite troubling for a large number of individuals. These conditions can be highly volatile and unpredictable, but we are still trying to determine how we can manage these variables and what preventive or treatment options may help patients who suffer from these conditions," said Alan Buchman, M.D., MSPH, AGAF, Feinberg School of Medicine of Northwestern University School of Medicine. "These two studies point to options that may help doctors manage symptoms in their patients and hopefully lead to better treatment options in the future."

Olfactory Receptors on Human Intestinal Enterochromaffin (EC) Cells Function as Sensors for Spices and Odorants (Abstract #W1581)

One primary research focus in GI disorders is how and why the system reacts to certain foods or other stimulants; specifically, researchers are investigating the primary factors responsible for regulating digestion. Enterochromaffin (EC) cells, which are present throughout the digestive system, release serotonin (a chemical associated with the etiology of various diseases such as migraine, diarrhea, respiratory disturbances and hypertension) and are important in regulating gut motility. Researchers from the Technical University of Munich and the Ludwig Maximillian University of Munich in Germany investigated whether EC cells in the intestine express nasal olfactory receptors (ORs, receptors used for smelling) to determine whether odorants present in spices, fragrances, cigarettes, detergents and cosmetics may cause serotonin release, thereby provoking a GI response.

To evaluate this connection, researchers studied human EC cells isolated from mucosal biopsies by laser microdissection and an EC derived cell line. The experiments revealed expression of several ORs in the isolated EC cells, as well as the cell line. Using digital fluorescence imaging, the team found that activation of the cells with odorants caused elevation of intracellular Ca2+, followed by serotonin release up to 10-fold that of the controls. Odorants like thymol (thyme), eugenol (cloves), bourgeonal (floral, lily-of-the-valley), helional (brown algae) and substances present in roses, bananas or raspberries, specifically, caused an elevation of Ca2+ levels.

The findings suggest that these types of odorants may cause a serotonin-related GI reaction. The effects could be inhibited by known OR antagonists, such as methyl isoeugenol (a competitive antagonist of eugenol) or by blocking Ca2+ influx (e.g., via Ca2+ channels with nifedipine, a drug used in the treatment of hypertension because it relaxes blood vessels).

"Our results show that odorants present in the gut may stimulate serotonin release via olfactory receptors expressed in human enterochromaffin cells in the gut mucosa," said Petra Voland, Ph.D., of the Technical University of Munich, and one of the lead investigators of the study. "Serotonin controls peristalsis and is implicated in pathological conditions such as vomiting, diarrhea and irritable bowel syndrome. Thus, olfactory receptors are potential novel targets for the treatment of gastrointestinal diseases and motility disorders."

Dr. Voland will present this study on Wednesday, May 23, at 8:00 a.m. in Hall E.
http://www.medilexicon.com/medicalnews.php?newsid=71770∞

New Treatments Needed For Irritable Bowel Syndrome

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11 May 2007

More effective remedies for Irritable Bowel Syndrome (IBS) are needed, as well as increased availability of treatments shown to be effective against IBS, such as hypnosis, says a Comment in this week's special gastroenterology edition of The Lancet.

The Comment is authored by Professor Robin Spiller, Wolfson Digestive Diseases Centre, University Hospital Nottingham, UK.

He says: "IBS is one of the commonest reasons for a consultation. However, because the disorder is poorly understood, many doctors find patients with IBS difficult to treat.

"Although extra time and effort may be needed, successful management is rewarding because it can substantially improve quality of life."

IBS has a similar incidence in Europe and the USA, and is increasingly recognised in developing countries, with between 5 - 10% of the population estimated to be affected.

Patients who present with IBS are typically female, aged 20 - 40 years. Most patients have abdominal pain or discomfort intermittently, with flares of pain lasting two to four days. Other symptoms include bloating, abnormal stool frequency and abnormal defecation.

IBS is also associated with psychological distress, with 50% of IBS patients who seek medical care also suffering stress or anxiety. IBS patients also have substantially increased health- care costs, with patients consulting their primary-care physician twice as often as non-IBS patients. A third of IBS patients are referred to secondary care and also onto sometimes unnecessary specialties.

Professor Spiller says: "Most IBS patients require reassurance, explanation and lifestyle advice."

The effects of modifying the diet of IBS sufferers is uncertain - trials have shown systematic exclusion of certain foods (e.g. wheat, dairy products) helped around half the patients in an uncontrolled trial, but how much of this was placebo response was unclear.

Psychological treatments have helped patients cope with IBS but generally without improving their bowel symptoms. Hypnosis has proven beneficial is randomised trials, including the long term, but limited availability of this treatment is a major drawback.

Most doctors and most (but not all) patients prefer to use drug therapy, ranging from antispasmodics to treat pain to serotonin antagonists to combat urgency and diarrhoea, and soluble fibres to improve pain and bowel habit. Tricyclic antidepressants can also prevent pain especially where diarrhoea is one of the symptoms present. But true drug effects in trials (10 - 15%) were smaller than the placebo effect (40 - 50%).

www.lancet.com
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