On-Site PhD conferral Zsa Zsa Regina Maria Weerts
Supervisors: Prof. dr. A.A.M. Masclee, Prof. dr. D.M.A.E. Jonkers
Co-supervisor: Dr. D. Keszthelyi
Key words: Irritable Bowel Syndrome, peppermint oil, transient receptor potential channels, cost-effectiveness
"Irritable Bowel syndrome; from diagnostic criteria to targeted treatment"
Transient receptor potential channels are promising targets for treatment of Irritable Bowel Syndrome (IBS). The TRPM8 channel can be stimulated by low temperatures and by menthol. We showed that intestinal TRPM8 expression is significantly higher in patients with IBS than healthy controls. The TRPM8 channel is colocalized with immune cells close to sensory nerve endings and its stimulation led to a reduction in pro-inflammatory cytokines. These findings suggest a role for TRPM8 in neuro-immune disease mechanisms in IBS. Menthol, which can stimulate the TRPM8 channel in the intestine, is the main constituent of peppermint oil. This research showed in a double-blind, randomized clinical trial of 189 IBS patients that small-intestinal release peppermint oil is a moderately effective treatment for irritable bowel syndrome with positive effects on IBS symptom severity, abdominal pain and abdominal discomfort. A trial-based cost-effectiveness analysis showed that peppermint oil appears to be cost-effective. Its use, which is low-cost, can therefore be justified by the effect on abdominal pain and the modest increase in quality of life in patients with IBS.