Update in the therapeutic management of irritable bowel syndrome

The value of eliminating foods according to food-specific immunoglobulin G antibodies in irritable bowel syndrome with diarrhoea

OBJECTIVE

This study investigated the role of food intolerance in irritable bowel syndrome with diarrhoea (D-IBS).

METHODS

Specific immunoglobulin G (IgG) antibodies against 14 common food antigens in the serum were measured in 77 patients with D-IBS and 26 healthy controls. Food-specific IgG antibodies were identified in 39 (50.65%) patients with D-IBS patients compared with four (15.38%) controls. For 12 weeks following the serological testing, 35 patients with D-IBS and food intolerance consumed diets that excluded the identified food. Changes in the main symptoms of D-IBS were evaluated before treatment and regularly during treatment in these patients.

RESULTS

After 4 weeks' dietary therapy, most symptoms of D-IBS had improved. By 12 weeks, all symptom scores had decreased significantly compared with the baseline scores.

CONCLUSIONS

The 12-week specific-food exclusion diets resulted in significant improvements in abdominal pain (bloating level and frequency), diarrhoea frequency, abdominal distension, stool shape, general feelings of distress and total symptom score compared with baseline in patients with D-IBS.

Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics

OBJECTIVE

In Irritable Bowel Syndrome, the gut-associated immune system may be up-regulated resulting in immune complex production, low-grade inflammation, loss of Class I bacteria, and translocation of inflammatory mediators and macromolecules outside of the GI lumen. Since food intolerance may be one of the reasons for this upregulation, our goal was to investigate the role of food intolerance in IBS patients.

METHODS

In this open label pilot study, we enrolled 20 patients with IBS by Rome II criteria (15 women, ages 24-81) who had failed standard medical therapies in a tertiary care GI clinic. Baseline serum IgE and IgG food and mold panels, and comprehensive stool analysis (CSA) were performed. Breath-hydrogen testing and IBS Quality-of-Life (QOL) questionnaires were obtained. Patients underwent food elimination diets based on the results of food and mold panels followed by controlled food challenge. Probiotics were also introduced. Repeat testing was performed at 6-months. We followed up with this cohort at 1 year after trial completion to assess the reported intervention and for placebo effect.

RESULTS

Baseline abnormalities were identified on serum IgG food and mold panels in 100% of the study subjects with significant improvement after food elimination and rotation diet (p < 0.05). Significant improvements were seen in stool frequency (p < 0.05), pain (p < 0.05), and IBS-QOL scores (p < 0.0001). Imbalances of beneficial flora and dysbiotic flora were identified in 100% of subjects by CSA. There was a trend to improvement of beneficial flora after treatment but no change in dysbiotic flora. The 1-year follow up demonstrated significant continued adherence to the food rotation diet (4.00 +/- 1.45), minimal symptomatic problems with IBS (4.00 +/- 1.17), and perception of control over IBS (4.15 +/- 1.23). The continued use of probiotics was considered less helpful (3.40 +/- 1.60).

CONCLUSION

These data demonstrate that identifying and appropriately addressing food sensitivity in IBS patients not previously responding to standard therapy results in a sustained clinical response and impacts on overall well being and quality of life in this challenging entity.

A patient follow-up survey programme for alosetron: assessing compliance to and effectiveness of the risk management programme

BACKGROUND

In November 2002, alosetron HCl (Lotronex, GlaxoSmithKline Research Triangle Park, NC, USA) was re-introduced to the US marketplace for women with severe diarrhoea-predominant irritable bowel syndrome. In support of the re-introduction, a risk management programme was implemented, which included a patient follow-up study in which all users of alosetron could participate.

AIM

We report on the methods used and the effectiveness of key elements of the risk management programme.

METHODS

Patients voluntarily enroled in the study and completed questionnaires at baseline, after 5 and 10 weeks, and quarterly thereafter. Questions focussed on patient eligibility, knowledge of risks and benefits, and adherence to the recommended programme elements for education, prescribing and dispensing.

RESULTS

Between December 2002 and 2004, 4,803 patients enrolled in the study, and <3% were lost to follow-up. The average follow-up time was approximately 6 months, and the response rate for each assessment was >95%. A total of 90% of patients at baseline met the full clinical criteria recommended for the treatment. Patient adherence to the risk management programme was >87%.

CONCLUSIONS

Using the Lotronex risk management programme, patients met clinical criteria, were knowledgeable about treatment risks and benefits, and were adherent to the process elements of the programme. These patients seemed to engage in active dialogue with their physicians about symptoms and use of alosetron.

Update in the pharmaceutical therapy of the irritable bowel syndrome

The therapeutic management of the irritable bowel syndrome (IBS) is ineffective and not satisfying either patients or practitioners. Research in functions of the enteric nervous system and its interaction with the central nervous system is the basis for the development of emerging pharmaceuticals in therapy of the IBS. These pharmaceuticals include agents such as opioid agonists, psychotropic agents and particularly serotonin receptor modulators. These novel pharmaceuticals aim to provide a more comprehensive approach in the therapy of the IBS and will serve both patients and practitioners. So far, the US Food and Drug Administration has approved two agents specifically for the treatment of the IBS, both belonging to the group of serotonin receptor modulators. However, questions remain whether a single therapy is sufficient in the management of IBS because this disease is influenced by biological and psychological as well as cultural and social factors.

Effect of pinaverium bromide on stress-induced colonic smooth muscle contractility disorder in rats

AIM

To investigate the effect of pinaverium bromide, a L-type calcium channel blocker with selectivity for the gastrointestinal tract on contractile activity of colonic circular smooth muscle in normal or cold-restraint stressed rats and its possible mechanism.

METHODS

Cold-restraint stress was conducted on rats to increase fecal pellets output. Each isolated colonic circular muscle strip was suspended in a tissue chamber containing warm oxygenated Tyrode-Ringer solution. The contractile response to ACh or KCl was measured isometrically on ink-writing recorder. Incubated muscle in different concentrations of pinaverium and the effects of pinaverium were investigated on ACh or KCl-induced contraction. Colon smooth muscle cells were cultured from rats and (Ca(2+))(i) was measured in cell suspension using the Ca(2+) fluorescent dye fura-2/AM.

RESULTS

During stress, rats fecal pellet output increased 61 % (P<0.01). Stimulated with ACh or KCl, the muscle contractility was higher in stress than that in control. Pinaverium inhibited the increment of (Ca(2+))(i) and the muscle contraction in response to ACh or KCl in a dose dependent manner. A significant inhibition of pinaverium to ACh or KCl induced (Ca(2+))(i) increment was observed at 10(-6) mol/L. The IC(50) values for inhibition of ACh induced contraction for the stress and control group were 1.66X10(-6) mol/L and 0.91X10(-6) mol/L, respectively. The IC(50) values for inhibition of KCl induced contraction for the stress and control group were 8.13X10(-7) mol/L and 3.80X10(-7) mol/L, respectively.

CONCLUSION

Increase in (Ca(2+))(i) of smooth muscle cells is directly related to the generation of contraction force in colon. L-type Ca(2+) channels represent the main route of Ca(2+) entry. Pinaverium inhibits the calcium influx through L-type channels; decreases the contractile response to many kinds of agonists and regulates the stress-induced colon hypermotility.

Effect of areca on contraction of colonic muscle strips in rats

AIM: To investigate the effects of areca on the contractile activity of isolated colonic muscle strips in rats and mechanism involved.

METHODS: Each strip (LMPC, longitudinal muscle of proximal colon; CMPC, circular muscle of proximal colon; LMDC, longitudinal muscle of distal colon; CMDC, circular muscle of distal colon.) was suspended in a tissue chamber containing 5 mL Krebs solution (37 °C), bubbled continuously with 950 mL•L⁻¹ O₂ and 50 mL•L⁻¹ CO₂. The mean contractile amplitude (A), the resting tension (T), and the contractile frequency (F) were simultaneously recorded on recorders.

RESULTS: Areca dose dependently increased the mean contractile amplitude, the resting tension of proximal and distal colonic smooth muscle strips in rats (P < 0.05). It also partly increased the contractile frequency of colonic smooth muscle strips in rats (P < 0.05). The effects were partly inhibited by atropine (the resting tension of LMPC decreased from 0.44 ± 0.12 to 0.17 ± 0.03; the resting tension of LMDC decreased from 0.71 ± 0.14 to 0.03 ± 0.01; the mean contractile amplitude of LMPC increased from -45.8 ± 7.2 to -30.5 ± 2.9; the motility index of CMDC decreased from 86.6 ± 17.3 to 32.8 ± 9.3; P < 0.05 vs areca), but the effects were not inhibited by hexamethonium (P > 0.05).

CONCLUSION: Areca stimulated the motility of isolated colonic smooth muscle strips in rats. The stimulation of areca might be relevant with M receptor partly.