Martina Führer

Hypersensitivity for capsaicin in patients with functional dyspepsia

Abstract  The pathophysiology of functional dyspepsia is poorly understood, thus diagnostic and therapeutic options for this disease are limited. We assessed the relevance of a simple test for chemical hypersensitivity by applying an oral capsaicin load. After a preliminary dose‐finding study, 61 healthy controls and 54 functional dyspepsia patients swallowed a capsule containing 0.75 mg capsaicin. A graded questionnaire evaluated severity of symptoms before and after capsule ingestion; an aggregate symptom score was calculated by adding all symptom scores. Controls developed moderate symptoms (symptom score: 6.0 ± 4.1; median: 5.0). The 75% quartile (9.0) was considered the upper limit of normal. Functional dyspepsia patients had significantly higher symptom scores (10.0 ± 6.5) than controls. About 54% of functional dyspepsia patients tested positive; clinically this group was not different from the group testing negative besides being on average younger and suffering more from bloating. In additional 13 patients with functional dyspepsia who tested positive (symptom score: 15.8 ± 0.9), symptom response to placebo capsules (1.9 ± 0.6) was similar to controls. In reliability testing, the Cronbach α‐value of the capsaicin test was 0.86. The capsaicin test is a simple and non‐invasive method to detect a subgroup of functional dyspepsia with chemical hypersensitivity.

Long-term success of GUT-directed group hypnosis for patients with refractory irritable bowel syndrome: a randomized controlled trial.

OBJECTIVES:Gut-directed hypnotherapy (GHT) in individual sessions is highly effective in the treatment of irritable bowel syndrome (IBS). This study aimed to assess the long-term effect of GHT in group sessions for refractory IBS.METHODS:A total of 164 patients with IBS (Rome-III-criteria) were screened, and 100 refractory to usual treatment were randomized 1:1 either to supportive talks with medical treatment (SMT) or to SMT with GHT (10 weekly sessions within 12 weeks). The primary end point was a clinically important improvement on several dimensions of daily life (assessed by IBS impact scale) after treatment and 12-month follow-up. The secondary end point was improvement in general quality of life (QOL; Medical Outcome Study Short-Form-36), psychological status (Hospital Anxiety Depression Scale) and reduction of single IBS symptoms. Analysis was by intention to treat.RESULTS:A total of 90 patients received allocated intervention. After treatment, 28 (60.8%) out of 46 GHT patients and 18 (40.9%) out of 44 SMTs improved (absolute difference 20.0%; 95% confidence interval (CI): 0–40.2%; P=0.046); over 15 months, 54.3% of GHT patients and 25.0% of controls improved (absolute difference 29.4%; 95% CI 10.1–48.6%; P=0.004). GHT with SMT improved physical and psychological well being significantly more than SMT alone (P<0.001). Gender, age, disease duration and IBS type did not have an influence on the long-term success of GHT.CONCLUSIONS:GHT improves IBS-related QOL, is superior to SMT alone, and shows a long-term effect even in refractory IBS.

Effect of repeated, long term capsaicin ingestion on intestinal chemo- and mechanosensation in healthy volunteers

Abstract  Repeated ingestion of capsaicin over a prolonged period reduces symptoms in functional dyspepsia, but initially induces upper abdominal symptoms. Sensitizing chemonociception might be the cause for this initial effect of capsaicin. The aim was to evaluate the effect of prolonged capsaicin ingestion on duodenal chemo‐ and mechanonociception. Healthy subjects ingested capsules containing either 0.25 mg capsaicin tid (n = 8) or placebo (n = 8) for 28 days. Before (day 0) and after (day 29) capsule ingestion the duodenum was distended with a balloon and perfused with a capsaicin solution. Mechanically and chemically induced sensation was evaluated by a graded questionnaire. Aggregate perception scores were calculated. Perception scores during balloon distensions with 12 and 18 mmHg were significantly lower after 4 weeks capsaicin when compared to baseline (P < 0.05). Balloon volumes to induce first sensation (63 ± 14 mL (day 0) vs 92 ± 22 mL (day 29); P < 0.05) and discomfort (101 ± 12 mL vs 137 ± 22 mL; P = 0.05) where significantly higher after 4 weeks capsaicin application; balloon pressures to induce sensations were not significantly different. Intraluminal capsaicin application induced first sensation after 3.4 ± 1.5 min (day 0) and 7.5 ± 4.6 min (day 29) (P < 0.05) and discomfort after 15.9 ± 9.8 min and 22.4 ± 7.3 min (P < 0.05). The quality of perception was not altered by repeated capsaicin ingestion. In the placebo group, mechano‐ and chemonociception remained unaltered at day 29. Four weeks ingestion of capsaicin desensitized both chemonociceptive and mechanonociceptive pathways in healthy volunteers. Symptom reduction after prolonged treatment with capsaicin in dyspeptic patients might be attributed to a dual desensitizing effect of capsaicin on chemonociceptors and mechanonociceptors.

A placebo-controlled trial of an oral capsaicin load in patients with functional dyspepsia.

Background  The pathophysiology of functional dyspepsia is poorly understood. Visceral hypersensitivity may play a key role. We studied a previously validated test to assess chemical hypersensitivity in functional dyspepsia by applying an oral capsaicin load.

Duodenal chemosensitivity and mechanosensitivity in humans during acid and ethanol perfusion.

Introduction Chemical stimulation with capsaicin in the intestinal lumen induces abdominal pain, presumably through a mechanism involving the polymodal vanilloid receptor TRPV1 (transient receptor potential vanilloid receptor subtype 1). Other stimulators of TRPV1 include heat, acid or ethanol. We evaluated the effects of duodenal acid and ethanol exposure on chemosensitivity and mechanosensitivity in healthy volunteers. Methods In two placebo-controlled arms of the study, healthy volunteers received duodenal infusions of either hydrochloric acid (0.1 mol/l) (n=8) or ethanol (5% vol/vol) through an oroduodenal tube. Mechanosensitivity was tested applying pressure-controlled duodenal distensions and chemosensitivity was tested by duodenal perfusion with capsaicin (40 μg/ml; 2.5 ml/min). Quality and intensity of upper abdominal symptoms were evaluated with a graded questionnaire during mechanical and chemical stimulation of the duodenum. Results During hydrochloric acid infusion, capsaicin-induced perception was reduced (P<0.01) and latency to discomfort was increased from 24.5 min (25th/75th%:16.5/36 min) during placebo to 50 min (25.5/60 min) (P<0.01). Ethanol had no significant effect on chemosensitivity [latency to discomfort for placebo vs. ethanol: 26 min (18/40 min) vs. 20 min (9/60 min)] (P>0.05). Neither duodenal acidification nor ethanol altered mechanosensitivity significantly (P>0.05). Conclusion Duodenal acid activated mechanisms that lead to a decreased sensitivity for intraluminal capsaicin; these mechanisms might protect duodenal chemonociceptors from being sensitized by acid. Whether this mechanism is impaired in patients with upper gastrointestinal functional disease remains to be determined.

Clinical characteristics of functional dyspepsia depending on chemosensitivity to capsaicin

Augmented chemosensitivity to capsaicin has been demonstrated in approximately half of functional dyspepsia (FD) patients.

Gastric administration of garlic powder containing the trpa1- agonist allicin induces specific epigastric symptoms and gastric relaxation in healthy subjects

TRPA1 is an excitatory ion channel and is involved in sensory processes including thermal nociception and inflammatory pain. The allicin in garlic is a strong activator of the TRPA1 channel.