Sensitivity In Irritable Bowel Syndrome Patients Research Articles

Treatment of refractory irritable bowel syndrome with visceral osteopathy: Short‐term and long‐term results of a randomized trial

In light of the low efficiency of available drugs in treating irritable bowel syndrome (IBS), there has been a growing interest in its alternative therapies. The aim of this study was to evaluate the effectiveness of visceral osteopathy for IBS. In total, 31 consecutive refractory IBS patients were prospectively included in a randomized, crossover placebo-controlled study. Qualitative evaluation of depression and four symptoms including constipation, diarrhea, abdominal distension and abdominal pain before and after each phase of the study were conducted using visual analog scales, measures of rectal sensitivity and colonic transit time. One year after the study, the assessment of symptoms was performed again in all patients. Visceral osteopathy was associated with a significant amelioration of self-reported diarrhea, abdominal distension and abdominal pain, while constipation did not change significantly after this therapy. It was also associated with decreased rectal sensitivity, presenting as an increase in threshold volume, constant sensation volume and maximum tolerable volume (P < 0.001). However, no significant evolution of rectal sensitivity was observed when patients underwent placebo manipulations. Modifications of depression and total or segmental colonic transit time were not observed. One year after the end of this trial, symptom scores of diarrhea, abdominal distension and abdominal pain were significantly lower than those at enrollment (P < 0.05). This study suggests that visceral osteopathy improves short-term and long-term abdominal distension and pain, and also decreases rectal sensitivity in IBS patients.

PWE-062 Can magnetic neural stimulation improve anorectal sensitivity in IBS?

IntroductionVisceral pain is a major clinical problem being a primary feature of irritable bowel syndrome (IBS). Treatments for this condition are limited, but there is increasing evidence that neural stimulation...

The variation of tryptase expression in the colonic mucosa of patients with diarrhea-predominant irritable bowel syndrome and its effect on the visceral sensitivity

Objective To observe the variation of tryptase expression in the colonic mucosa of patients with diarrhea-predominant irritable bowel syndrome(IBS-D) and the effects of their colonic mucosa cultured supernatants on mice visceral sensitivity. Methods The IBS-D patients study: of twenty-four patients with IBS-D and 12 healthy volunteers, four mucosal biopsies of each individual were collected at ascending colon under colonoscopy. The quantity of mucosal mast cells were detected by toluidine blue stains, and the tryptase concentration of colonic mucosa cultured supernatants were determined by enzyme-linked immunosorbent assay (ELISA). Animal experiments: fifty-six male six to eight weeks old C57BL/6 mice were divided into 7 groups and then were administrated with healthy volunteer's ascending colonic mucosa-cultured supernatants 100 μl (group A), IBS-D patient' s ascending colonic mucosa-cultured supernatants 100 μl (group B), IBS-D ascending colonic mucosacultured supernatants 100 μl with Fut-175(50 μg/ml, group C), tryptase with different concentration:0.6 ng (group D), 2.2 ng (group E), tryptase 2.2 ng with Fut-175 (group F), and 0.9% sodium chloride as control (group G) respectively. After six hours, the abdominal myoelectric activities (AMAs) were recorded during colorectal balloon distension (CRD), and the expressions of substance P (SP), Calcitonin gene-related peptide (CGRP) in spinal dorsal horn of lumbosaeral region were detected by immunohistochemistry. Results The number of mast cells in the ascending colon of patients with IBS-D [6.33 ± 1.64) / HP] was higher than that in controls [(3.08 ± 0.77 ) / HP], the difference was statistical significant (P = 0.000). The tryptase concentration of ascending colonic mucosa cultured supernatants in IBS-D patients [(0. 072 ± 0. 023) ng/mg] was higher than that in controls [(0.026 ± 0.014) ng/mg], the difference was statistical significant ( P = 0. 000). In animal experiments, when the inside pressure of balloon was 30, 45, 60 mmHg, respectively, the AMAs value in group B [(27.50±5.23), (41.69±5.80), (54. 03±6.13) μV, respectively] and group E [(27. 05±1.66), (40. 66±3.39), (54. 38± 4.68) μV, respectively] were significantly higher than those in group A, group C, group D, group F and group G (P＜0. 05, respectively). The average integrated option densities (IOD) of SP and CGRP in spinal dorsal horn in groupB (121.72 ± 4.67,123.54±4.32)and E (124.69±5.06,126.32±5.09) were higher than in group A, group C, group D,group F and group G (P＜0.05, respectively). Conclusion The quantity of mast cell and the content of tryptase in the ascending colonic mucosa of IBS-D patients increased significantly. And their colonic mucosa cultured supernatants caused the mice visceral hypersensitivity, which indicated that tryptase may involved in the variation of visceral sensitivity in IBS-D patients. Key words: Irritable bowel syndrome; Mast cells; Tryptases; Visceral sensitivity; Substance P; Calcitonin gene-related peptide

Rectal Visceral Sensitivity in Women with Irritable Bowel Syndrome without Psychiatric Comorbidity Compared with Healthy Volunteers

Background. Psychiatric comorbidity and visceral hypersensitivity are common in patients with irritable bowel syndrome (IBS), but little is known about visceral sensitivity in IBS patients without psychiatric disorders. Aim. We wanted to examine rectal visceral sensitivity in IBS patients without comorbid psychiatric disorders, IBS patients with phobic anxiety and healthy volunteers. Methods. A total of thirty-eight female, non-constipated IBS patients without psychiatric disorders and eleven female IBS patients with phobic anxiety were compared to nine healthy women using a barostat double random staircase method. The non-psychiatric patients were divided into those with diarrhoea predominant symptoms and those with alternating stool habits. Results. The IBS patients without psychiatric disorders had normal visceral pressure thresholds. However, in the diarrhoea predominant subgroup, the volume discomfort threshold was reduced while it was unchanged in those with alternating stool habits. The phobic IBS patients had similar thresholds to the healthy volunteers. The rectal tone was increased in the non-psychiatric IBS patients with diarrhoea predominant symptoms and in the IBS patients with phobic anxiety. Conclusions. Non-constipated IBS patients without psychiatric disorders had increased visceral sensitivity regarding volume thresholds but normal pressure thresholds. Our study suggests that the lowered volume threshold was due to increased rectal tone.

Distension technique influences the relationship between colonic and rectal hypersensitivity in irritable bowel syndrome

In irritable bowel syndrome (IBS), it remains unclear whether rectal hypersensitivity is a 'marker' of colonic hypersensitivity. Our aim was to examine the relation between colonic and rectal sensitivity in IBS patients, comprising phasic and ramp distension techniques. Twenty IBS patients and 12 healthy subjects (N) underwent stepwise ramp and random phasic barostat distensions in the colon and rectum in random order. The sensory threshold pressure (ramp distension) and the visual analogue scale score (VAS, phasic distension), for pain and non-pain, were recorded. Colonic thresholds were lower, and VAS scores were generally higher, for pain and non-pain sensitivities in IBS compared to N. Rectal thresholds were lower, and VAS scores were higher, for pain but not for non-pain, in IBS compared to N. In IBS, for phasic distension, there was good correlation between the colon and rectum for non-pain (e.g. at 16 mmHg, r=0.59, P=0.006) and pain (r=0.60, P=0.006) sensitivities. In contrast, there was no significant correlation between the colon and rectum for ramp distension. In conclusion, colonic and rectal sensitivity in IBS are correlated in response to phasic but not ramp barostat distensions. The rectum serves as a legitimate 'window' for evaluating colonic hypersensitivity in IBS, provided that phasic distensions are employed.

The selective serotonin reuptake inhibitor fluoxetine does not change rectal sensitivity and symptoms in patients with irritable bowel syndrome: A double blind, randomized, placebo-controlled study

Background & Aims: Although widely prescribed, the evidence for the use of antidepressants for the treatment of irritable bowel syndrome (IBS) is limited. In this study, we hypothesized that fluoxetine (Prozac), a selective serotonin reuptake inhibitor, has visceral analgesic properties, leading to increased sensory thresholds during rectal distention and improvement of symptoms, in particular in IBS patients with visceral hypersensitivity. Methods: Forty non-depressed IBS patients underwent a rectal barostat study to assess the sensitivity to rectal distention before and after 6 weeks of treatment with fluoxetine 20 mg or placebo. Abdominal pain scores, individual gastrointestinal symptoms, global symptom relief, and psychologic symptoms were assessed before and after the intervention. Results: At baseline, 21 of 40 patients showed hypersensitivity to rectal distention. Fluoxetine did not significantly alter the threshold for discomfort/pain relative to placebo, either in hypersensitive (19 ± 3 vs. 22 ± 2 mm Hg above MDP) or in normosensitive (34 ± 2 vs. 39 ± 4 mm Hg above MDP) IBS patients. Overall, 53% of fluoxetine-treated patients and 76% of placebo-treated patients reported significant abdominal pain scores after 6 weeks (not significant). In contrast, in hypersensitive patients only, fluoxetine significantly reduced the number of patients reporting significant abdominal pain. Gastrointestinal symptoms, global symptom relief, and psychologic symptoms were not altered. Conclusions: Fluoxetine does not change rectal sensitivity in IBS patients. Possible beneficial effects on pain perception need to be confirmed in larger trials.

Role of opioid ligands in the irritable bowel syndrome.

Endogenous opioid peptides - enkephalins, beta-endorphin and dynorphins - are located in specific sites of the brain, the spinal cord, the autonomic ganglia and the enteric nervous system. Endogenous opioids participate in the regulation of nervous visceral afference and sensitivity as well as of several visceral motor function induced by the central nervous system and through the enteroenteric and the myoenteric reflexes. Their final effect on gut physiology is the net and harmonically balanced result of their binding to mu, delta and kappa opioid receptor subtypes. Exogenous opioid receptor ligands with different affinities for the opioid receptor subtypes have been effectively used to modify and normalize altered gut functions. The mu receptor agonists - morphine and, to a greater extent, the meperidine congeners diphenoxylate and loperamide - have been shown to slow gastrointestinal transit by their effects on the circular and longitudinal muscle of the intestine. Diphenoxylate and, more efficiently, loperamide, for the lack of any effect on the central nervous system, have been usefully employed in the treatment of diarrhea in irritable bowel syndrome (IBS) patients. Unlike the mu receptor agonists morphine and loperamide, which invariably stimulate colonic motility, trimebutine, which has almost equal affinity for mu, delta and kappa receptors, has no effect on normal colonic activity but reduces the abnormal increase in postprandial motor activity in IBS patients and accelerates slow large bowel transit in constipated patients. Opioid ligands can be usefully employed to normalize altered visceral sensitivity in IBS patients. The kappa receptor agonist fedotozine exerts its antinociceptive effect by acting on peripheral nerve endings of sensory vagal and nonvagal afferent pathways. Fedotozine has been shown to increase the threshold of perception to colonic distension in experimental conditions and to affect favourably symptoms of IBS in clinical trials.