Motility disorders and stress

Gastric Motor Functions in Patients With Mood Disorders and Functional Gastroduodenal Symptoms

OBJECTIVE

Functional gastroduodenal symptoms (FGDSs) may result from perturbations in gastric emptying (GE) and gastric accommodation (GA), which are variably affected by acute stress. This study aimed to examine whether individuals who have both mood disorder and FGDS exhibit differences in GE and GA using standardized, validated, and reproducible noninvasive methods.

METHODS

Using a data retrieval program, 1554 individuals at a single center were identified after having undergone measurements of GE by scintigraphy of a 99mTc-radiolabeled egg (320 kcal, 30% fat meal) and GA by single-photon emission computed tomography to assess the underlying pathophysiology in FGDS. An extensive medical record review identified 267 of these individuals as having diagnoses of depression, anxiety, or comorbid anxiety/depression (CAD). Differences in GE and GA as related to the presence of anxiety or depressive disorders were analyzed using one-way analysis of variance on ranks and Mann-Whitney tests for the two-group comparisons.

RESULTS

Sixty-three patients with anxiety, 134 with depression, and 70 with CAD were identified. GE at 1 hour was slower (p = .04) and GE at 2 hours numerically decreased (p = .07) for depression compared with anxiety. GA was diminished for CAD compared with anxiety (p = .04) and depression (p = .009). There were no differences in fasting gastric volume or GE at 4 hours.

CONCLUSIONS

In this study examining GE and GA in anxiety and depressive disorders among patients with FGDS, the combined presence of anxiety and depression was associated with impaired GA compared with patients with depression or anxiety alone, and early GE seemed to be slower in those with depression compared with patients with anxiety.

Clinical, psychological, and physiological correlates of patients who defecate after meal

BACKGROUND AND AIMS

Food is the most important synchronizer of gastrointestinal motility and secretion. Many patients with functional bowel or anorectal disorders complain of fecal urge and stool output after eating.

PATIENTS AND METHODS

In this prospective observational study, 408 consecutive outpatients with functional bowel and/or anorectal disorders (74% female, 50.2±15.6 years, 24.8±5.0 kg/m²) filled Rome III questionnaires. Depression and anxiety scores, a physiological evaluation (total and segmental colonic transit time, colonic transit response to eating using a standard 1000 kcal test meal, and anorectal manometry), were measured. Univariate analysis and multivariate logistic regression were carried out according to the presence or not of stool output after eating.

RESULTS

Defecation after eating was found in 21% of patients. These patients were not different according to the demographic characteristics of sex ratio (P=0.702), age (P=0.830), and BMI (P=0.314). In contrast, they had lower state anxiety (P=0.032), but similar scores of depression (P=0.240) and trait anxiety (P=0.933). They had similar manometric characteristics (anal pressure and rectal sensitivity), but a greater response to eating in all segments of the colon. There was an increase in the frequency of functional diarrhea (odds ratio=2.576, 95% confidence interval=1.312-5.056; P=0.006) and levator ani syndrome (odds ratio=2.331, 95% confidence interval=1.099-4.944; P=0.017), but no other functional bowel disorder including irritable bowel syndrome and its subtypes was found.

CONCLUSION

Stool output after eating is associated with clinical disorders but not physiological parameters. This symptom is not associated with irritable bowel syndrome, but a higher frequency of functional diarrhea.

Dietary Triggers in Irritable Bowel Syndrome: Is There a Role for Gluten?

A tight link exists between dietary factors and irritable bowel syndrome (IBS), one of the most common functional syndromes, characterized by abdominal pain/discomfort, bloating and alternating bowel habits. Amongst the variety of foods potentially evoking "food sensitivity", gluten and other wheat proteins including amylase trypsin inhibitors represent the culprits that recently have drawn the attention of the scientific community. Therefore, a newly emerging condition termed non-celiac gluten sensitivity (NCGS) or nonceliac wheat sensitivity (NCWS) is now well established in the clinical practice. Notably, patients with NCGS/NCWS have symptoms that mimic those present in IBS. The mechanisms by which gluten or other wheat proteins trigger symptoms are poorly understood and the lack of specific biomarkers hampers diagnosis of this condition. The present review aimed at providing an update to physicians and scientists regarding the following main topics: the experimental and clinical evidence on the role of gluten/wheat in IBS; how to diagnose patients with functional symptoms attributable to gluten/wheat sensitivity; the importance of double-blind placebo controlled cross-over trials as confirmatory assays of gluten/wheat sensitivity; and finally, dietary measures for gluten/wheat sensitive patients. The analysis of current evidence proposes that gluten/wheat sensitivity can indeed represent a subset of the broad spectrum of patients with a clinical presentation of IBS.

Glyphosate affects the spontaneous motoric activity of intestine at very low doses - in vitro study

Glyphosate is an active substance of the most popular herbicides worldwide. Its common use results from the belief that it affects exclusively plants. However, studies on glyphosate and its trade formulations reveal that it causes numerous morphological, physiological and biochemical disturbances in cells and organisms of animals, including mammals. Due to the fact that shortly after oral exposure glyphosate is detected in the highest amount in small intestine, the aim of this study was to evaluate the effect of this compound on the spontaneous motoric activity of intestine under in vitro conditions. The experiments were conducted on rat jejunum strips under isotonic conditions. The strips were incubated in buffered (pH 7.35) and non-buffered (pH 5.2) glyphosate solutions ranged from 0.003 to 1.7 g/L. The results indicate that glyphosate applied in buffered solution affects significantly the spontaneous motoric activity of rat isolated jejunum strips. The muscle response is biphasic (miorelaxation accompanied by contraction). The contraction is observed already at a dose of 0.003 g/L and the first significant biphasic reaction at a dose of 0.014 g/L. The incubation of jejunum strips with glyphosate in non-buffered solution (pH 5.2) results in a different reaction. The smooth muscle undergoes only persistent relaxation, which is stronger than the response to glyphosate solution in pH 7.35. Motility disturbances are also observed after glyphosate removal from the incubation solution. The gathered data suggests that glyphosate impairs gastrointestinal strips' motility at concentration that are noticed in human exposed to non-toxic doses of glyphosate.

Candidate genes and sensory functions in health and irritable bowel syndrome

Adrenergic and serotonergic (ADR-SER) mechanisms alter gut (GI) function; these effects are mediated through G protein transduction. Candidate genetic variations in ADR-SER were significantly associated with somatic scores in irritable bowel syndrome (IBS) and gastric emptying but not small bowel or colonic transit. Our aim was to assess whether candidate ADR-SER genes are associated with motor and sensory GI functions in IBS and subgroups on the basis of bowel dysfunction. In 122 patients with IBS and 39 healthy controls, we assessed gastrointestinal somatic symptoms and affect by validated questionnaires. We measured: gastric volume (GV), maximum tolerated volume, rectal compliance, sensation thresholds and ratings, and genetic variations including alpha2A (C-1291G), alpha2C (Del 332-325), GNbeta3 (C825T), and 5-HTTLPR. Demographics and genotype distributions were similar in the patients with IBS subgrouped on bowel function. There were significant associations between 5-HTTLPR SS genotype and absence of IBS symptoms and between 5-HTTLPR LS/SS genotype and increased rectal compliance and increased pain ratings, particularly at 12 and 24 mmHg distensions. GNbeta3 was associated only with fasting GV; we did not detect associations between alpha2A genotype and the gastrointestinal sensory or motor functions tested. We concluded that 5-HTTLPR LS/SS genotype is associated with both increased pain sensation and increased rectal compliance though the latter effect is unlikely to contribute to increased pain sensation ratings with LS/SS genotype. The data suggest the hypotheses that the endophenotype of visceral hypersensitivity in IBS may be partly related to genetic factors, and the association of GNbeta3 with fasting GV may explain, in part, the reported association of GNbeta3 with dyspepsia.

Irritable bowel syndrome: quality of life and nursing interventions

Irritable bowel syndrome (IBS) is a functional bowel disorder. It is one of the most common gastrointestinal diseases diagnosed in medical practice and can account for up to 50% of referrals to gastroenterology outpatient clinics. IBS remains a poorly understood and mysterious medical condition. Individuals can suffer from abdominal pain and abnormal bowel function for unexplained reasons and the impact of these symptoms can have a detrimental affect on health-related quality of life. In this article the incidence, causes, diagnosis and management of IBS are addressed. Specific attention is given to the nursing role in the management of this chronic condition.

Perceived psychologic stress and colorectal cancer mortality: findings from the Japan Collaborative Cohort Study

OBJECTIVE

The purpose of this research was to examine the relationship between perceived psychologic stress and colorectal cancer mortality in a prospective large-scale study.

METHODS

Between the years 1988 and 1990, 32,153 men and 45,854 women aged 40 to 79 years were enrolled. Participants completed a self-administered questionnaire that addressed demographic, lifestyle, and psychosocial characteristics. Subjects were subsequently followed for mortality until the end of 1999. Perceived psychologic stress was assessed using the question "Do you feel stress during your daily life?" The 4 possible responses, ranging from "little or none" (1) to "extreme" (4), were dichotomized as low (1 or 2) or high (3 or 4) stress. Relative risks (RRs) with 95% confidence intervals (CIs) for colon and rectal cancer according to the perceived level of stress were estimated using Cox's proportional hazard model.

RESULTS

During the follow-up period (average, 9.6 years), 193 colon cancer deaths (96 men and 97 women) and 127 rectal cancer deaths (88 men and 39 women) were confirmed within the study group. Women who reported high stress had a 1.64-fold higher risk of colon cancer mortality (multivariate-adjusted RR, 1.64; 95% CI, 1.01-2.66) compared with those reporting low stress. There was no significant association between perceived stress and female rectal cancer or male colon and rectal cancer mortality.

CONCLUSIONS

Perceived psychologic stress was weakly associated with increased mortality from colon cancer in women. No positive or inverse association was found in men. Further studies are needed to confirm our results.

Inhibitory effects of stress on postprandial gastric myoelectrical activity and vagal tone in healthy subjects

The aim was to investigate gastric myoelectrical activity (GMA) and vagal activity in response to stress. The study was performed in 10 healthy subjects in three sessions (control, relaxation and stress). The control session was composed of 30-min recordings before and 30-min recordings after a test meal. The protocol of two other sessions was similar except that the fasting recording was extended to 60 min and the subjects were continuously watching a horror movie (stress) or guided meditation tape (relaxation) after the 30-min baseline. GMA was recorded using electrogastrography and heart rate variability (HRV) was derived from the electrocardiogram. Meal resulted in a postprandial increase in the dominant frequency (2.91 cpm vs 3.17 cpm, P < 0.007), dominant power (30.0 dB vs 32.5 dB, P < 0.05), and percentage of normal slow waves (79.8%vs 87.4%, P = 0.09). Similar responses were found in the relaxation session. Stress inhibited all these normal postprandial response and reduced the regularity of gastric slow waves (82.0%vs 66.0%, P < 0.01). In addition, spectral analysis of the HRV demonstrated an inhibition of postprandial vagal activity and an increase of postprandial sympathetic activity with stress. Stress has an inhibitory effect on postprandial GMA and this may involve both vagal and sympathetic pathway.

Electrogastrography as a diagnostic tool for delayed gastric emptying in functional dyspepsia and irritable bowel syndrome

Several pathophysiological mechanisms have been proposed in functional gastrointestinal (GI) disorders, e.g. altered GI motility and sensitivity. The aim of this study was to investigate gastric electrical activity (GEA) in patients with functional dyspepsia (FD) or irritable bowel syndrome (IBS) compared with healthy controls (HC), and to assess if abdominal symptoms and delayed gastric emptying are associated with alterations in GEA, as determined by electrogastrography (EGG). Forty patients with FD, IBS or both were compared with 22 HC. EGG was performed before and after a standard meal. Frequencies and amplitudes pre- and post-prandially were analysed. Furthermore, gastric emptying and symptom scores were assessed. Eight of 40 patients (20%; three FD, three IBS, two FD and IBS) had delayed gastric emptying. Disturbed gastric emptying and lack of a postprandial increase in the EGG amplitude were significantly correlated (r = 0.8; P < 0.005). No differences between controls and patients were observed in the distribution of EGG frequencies. Treatment with the prokinetically active macrolide erythromycin improved gastric emptying, GEA and symptoms (n = 4). The data suggest that EGG could be useful as a diagnostic tool in patients with FD and IBS to identify a subgroup of patients with delayed gastric emptying.

Tegaserod maleate in the treatment of irritable bowel syndrome: a clinical review

BACKGROUND

Approved in July 2002, tegaserod maleate is a partial 5-hydroxytryptamine 4-receptor agonist used to improve symptoms of constipation-predominant irritable bowel syndrome (IBS). The physiologic actions of tegaserod relate to its ability to stimulate gastric and intestinal motility.

OBJECTIVE

This article reviews available data on the pharmacokinetic and pharmacodynamic properties and clinical efficacy of tegaserod.

METHODS

Searches of MEDLINE and PubMed from 1966 to the present were conducted using the search terms tegaserod, tegaserod maleate, irritable bowel syndrome, and Rome criteria. Abstracts presented at national meetings between 1997 and 2002 were reviewed and included if perceived to be reliable and relevant.

RESULTS

In clinical trials, tegaserod was associated with significantly better scores on the subject's global assessment of relief compared with placebo (P < 0.05). The absolute efficacy of tegaserod compared with placebo varied between trials and averaged 10% to 12%. Tegaserod had a good safety profile; diarrhea was the only adverse effect that occurred more often in tegaserod recipients than in placebo recipients. No electrocardiographic changes were observed at therapeutic concentrations of tegaserod. Long-term (1-year) treatment with tegaserod appeared to be well tolerated. The recommended dosage for patients aged >18 years with constipation-predominant IBS is 6 mg PO BID before meals for 4 to 6 weeks, with an additional 4 to 6 weeks of treatment if initial therapy is partially effective.

CONCLUSIONS

The addition of tegaserod to the arsenal of moderately effective medication currently used in the treatment of IBS may be helpful in patients with constipation-predominant IBS. Continuous postmarketing surveillance and reporting of adverse reactions are essential to further characterize the safety profile of this new agent.

Irritable bowel syndrome patients show enhanced modulation of visceral perception by auditory stress

OBJECTIVES

Symptoms in irritable bowel syndrome (IBS) patients are sensitive to psychological stressors. These effects may operate through an enhanced responsiveness of the emotional motor system, a network of brain circuits that modulate arousal, viscerosomatic perception, and autonomic responses associated with emotional responses, including anxiety and anger. The aim of this study was to test the primary hypothesis that IBS patients show altered perceptual responses to rectal balloon distention during experimentally induced psychological stress compared with healthy control subjects.

METHODS

A total of 15 IBS patients (nine women and six men) and 14 healthy controls (seven women and seven men) were studied during two laboratory sessions: 1) a mild stress condition (dichotomous listening to two conflicting types of music), and 2) a control condition (relaxing nature sounds). The stress and relaxation auditory stimuli were delivered over a 10-min listening period preceding rectal distentions and during the rectal distentions but not during the distention rating process. Ratings of intensity and unpleasantness of the visceral sensations, subjective emotional responses, heart rate, and neuroendocrine measures (norepinephrine, cortisol, adrenocorticotropic hormone [ACTH], and prolactin) were obtained during the study.

RESULTS

IBS patients, but not healthy controls, rated the 45-mm Hg visceral stimulus significantly higher in terms of intensity and unpleasantness during the stress condition compared with the relaxation condition. IBS patients also reported higher ratings of stress, anger, and anxiety during the stress compared with the relaxing condition, whereas controls had smaller and nonsignificant subjective responses. Heart rate measurements, but not other neuroendocrine stress measures, were increased under the stress condition in both groups.

CONCLUSION

These findings confirm the hypothesis of altered stress-induced modulation of visceral perception in IBS patients.

Clinical perspectives, mechanisms, diagnosis and management of irritable bowel syndrome

This consensus document reviews the current status of the epidemiology, social impact, patient quality of life, pathophysiology, diagnosis and treatment of irritable bowel syndrome. Current evidence suggests that two major mechanisms may interact in irritable bowel syndrome: altered gastrointestinal motility and increased sensitivity of the intestine. However, other factors, such as psychosocial factors, intake of food and prior infection, may contribute to its development. Management of patients is based on a positive diagnosis of the symptom complex, careful history and physical examination to exclude 'red flags' as risk factors for organic disease, and, if indicated, investigations to exclude other disorders. Therapeutic choices include dietary fibre for constipation, opioid agents for diarrhoea and low-dose antidepressants or infrequent use of antispasmodics for pain, although the evidence basis for efficacy is limited or in some cases absent. Psychotherapy and hypnotherapy are the subject of ongoing study. Treatment should be tailored to patient needs and fears. Novel therapies are emerging, and drugs acting on serotonin receptors have proven efficacy and a scientific rationale and, if approved, should be useful in the overall management of patients with irritable bowel syndrome. Patient and physician education, early identification of psychosocial issues and better therapies are important strategies to reduce the suffering and societal cost of irritable bowel syndrome.

Intrarectal injection of glycerol induces hypersensitivity to rectal distension in healthy subjects without modifying rectal compliance

BACKGROUND

Rectal sensory thresholds are lowered in patients with irritable bowel syndrome (IBS), reflecting visceral hyperlagesia, which might be related to subclinical inflammation.

AIM

To evaluate the effects of an intraluminal injection of glycerol, a mucosal irritant, on rectal tone and perception of distension in 12 healthy subjects.

METHODS

Rectal tone was evaluated with a barostat. First sensation, need to defecate and pain thresholds were evaluated during isobaric phasic distensions, before and 20 and 120 min after injection of 10 ml glycerol in the rectum.

RESULTS

Baseline bag volume (97.9 +/- 56.2 ml) significantly decreased 20 min (49.7 +/- 42.2 ml; P= 0.026) and 120 min (66.5 +/- 38.3 ml; P= 0.050) after injection of glycerol, indicating its hypertonic effect. The pressure defining sensory thresholds was decreased significantly 20 min after glycerol injection: first sensation, 14.6 +/- 2.9 versus 18.3 +/- 7.2 mm Hg (P = 0.01); need to defecate, 19.6 +/- 3.7 versus 26.0 +/- 6.9 mm Hg; pain, 23.8 +/- 4.5 versus 35.6 +/- 9.5 mm Hg (P = 0.001). This effect was maintained for 120 min after injection of glycerol. Slopes of the compliance curves did not differ before and after injection of glycerol.

CONCLUSIONS

Intraluminal injection of glycerol significantly increases rectal tone and sensitizes healthy volunteers to rectal distension, since they show significantly lower thresholds after glycerol. This could constitute a model of visceral hypersensitivity in healthy volunteers.

Management of the irritable bowel syndrome

Irritable bowel syndrome (IBS) is the most common disorder diagnosed by gastroenterologists and one of the more common ones encountered in general practice. The overall prevalence rate is similar (approximately 10%) in most industrialized countries; the illness has a large economic impact on health care use and indirect costs, chiefly through absenteeism. IBS is a biopsychosocial disorder in which 3 major mechanisms interact: psychosocial factors, altered motility, and/or heightened sensory function of the intestine. Subtle inflammatory changes suggest a role for inflammation, especially after infectious enteritis, but this has not yet resulted in changes in the approach to patient treatment. Treatment of patients is based on positive diagnosis of the symptom complex, limited exclusion of underlying organic disease, and institution of a therapeutic trial. If patient symptoms are intractable, further investigations are needed to exclude specific motility or other disorders. Symptoms fluctuate over time; treatment is often restricted to times when patients experience symptoms. Symptomatic treatment includes supplementing fiber to achieve a total intake of up to 30 g in those with constipation, those taking loperamide or other opioids for diarrhea, and those taking low-dose antidepressants or infrequently using antispasmodics for pain. Older conventional therapies do not address pain in IBS. Behavioral psychotherapy and hypnotherapy are also being evaluated. Novel approaches include alosetron; a 5-HT(3) antagonist, tegaserod, a partial 5-HT(4) agonist, kappa-opioid agonists, and neurokinin antagonists to address the remaining challenging symptoms of pain, constipation, and bloating. Understanding the brain-gut axis is key to the eventual development of effective therapies for IBS.

Effect of alpha-2 adrenoceptor antagonists on colonic function in rats

We studied the effect of alpha-2 adrenoceptor antagonists on colonic function stimulated by water-avoidance stress, 5-hydroxytryptamine (5-HT), bethanechol and castor oil by comparison with the effects of atropine and a 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, ondansetron. Yohimbine, idazoxan and atropine, but not ondansetron, significantly inhibited water-avoidance stress-stimulated faecal excretion. Yohimbine and idazoxan inhibited neither 5-HT- nor bethanechol-stimulated faecal excretion. In contrast, atropine inhibited both 5-HT- and bethanechol-stimulated faecal excretion and ondansetron inhibited 5-HT-stimulated faecal excretion. Yohimbine did not inhibit the incidence of diarrhoea induced by castor oil, but idazoxan significantly inhibited diarrhoea observed during a 1-h period after the administration of castor oil. Both atropine and ondansetron inhibited diarrhoea during a 2-h period after the administration of castor oil. These findings suggest that alpha-2 adrenoceptor antagonists specifically inhibit colonic motor function stimulated by stress in rats.

The combination of medical treatment plus multicomponent behavioral therapy is superior to medical treatment alone in the therapy of irritable bowel syndrome

OBJECTIVE

Although the standard treatments for the irritable bowel syndrome (IBS) are medical, growing evidence indicates the substantial therapeutic value of psychological therapy. However, it has not been investigated whether the combination of multicomponent behavioral therapy plus medical treatment is more effective than medical treatment alone. The aim of this study was to investigate this question in patients consulting a tertiary gastrointestinal (GI) referral center.

METHODS

Twenty-four IBS outpatients were randomly assigned to the combination of standardized multicomponent behavioral therapy plus standard medical treatment (SMBT) or standard medical treatment alone (SMT). SMBT included IBS information and education, progressive muscle relaxation, training in illness-related cognitive coping strategies, problem-solving, and assertiveness training in 10 sessions over 10 wk. SMT included standardized symptom-oriented medical treatment and regular visits to a gastroenterologist every second week. Posttreatment outcome measures consisted of quantification of GI, vegetative, and psychological symptoms by means of daily symptom diaries and the assessment of changes in rectovisceral perception thresholds, as well as of questionnaire measures on psychological distress, overall well-being, illness-related coping abilities, and quality of life. Follow-ups were conducted at 3- and 6-month intervals.

RESULTS

Pre- and posttreatment evaluations showed significantly (p < 0.01) greater IBS symptom reduction as measured by daily symptom diaries for the SMBT group than for the SMT group. Rectovisceral perception remained unchanged by either treatment. Overall well-being significantly improved in the SMBT group but remained unchanged in the SMT group. Subjects in the SMBT group, unlike those in the SMT group, felt significantly more in control of their health, and quality of life was significantly improved in the SMBT group but remained unchanged in the SMT group.

CONCLUSIONS

The data provide evidence that the combination of medical treatment plus multicomponent behavioral treatment is superior to medical treatment alone in the therapy of IBS.

The kappa agonist fedotozine relieves hypersensitivity to colonic distention in patients with irritable bowel syndrome

BACKGROUND & AIMS

Visceral hypersensitivity plays a major role in the pathophysiology of inflammatory bowel syndrome (IBS). Opioid kappa receptors on afferent nerves may modulate it and may be the target of new IBS treatments. The aim of this study was to evaluate the effects of fedotozine, a potent and selective kappa agonist, on responses to colonic distention and colonic compliance in patients with IBS.

METHODS

Fourteen patients with IBS (Rome criteria; 50 +/- 12 years; 6 men and 8 women) were included in a randomized double-blind, crossover trial comparing the effect of an intravenous infusion of 100 mg fedotozine or saline on sensory thresholds elicited by left colon phasic distention (4-mm Hg steps for 5 minutes) up to a sensation of abdominal pain. Colonic compliance was compared by the slope of the pressure-volume curves built on placebo and on fedotozine.

RESULTS

In the fedotozine group, thresholds of first perception (28.7 +/- 5.9 mm Hg) and pain (34.7 +/- 5.5 mm Hg) were significantly greater than with placebo (23.3 +/- 4.5 and 29.0 +/- 3.5 mm Hg, respectively; P = 0.0078). Colonic compliance was 9. 20 +/- 3.87 mL. mm Hg-1 with placebo and 8.73 +/- 3.18 mL. mm Hg-1 with fedotozine (not significant).

CONCLUSIONS

Fedotozine increases thresholds of perception of colonic distention in patients with IBS without modifying colonic compliance. Fedotozine seems capable of reversing visceral hypersensitivity observed in these patients and could have some beneficial action on their symptoms.

Relevance of gastrointestinal motor disturbances in functional dyspepsia

Gastrointestinal motor abnormalities are frequent findings in patients with functional dyspepsia. However, these abnormalities are rather non-specific and seem to be restricted to a proportion of patients. Furthermore, they are not necessarily time-linked to symptom perception. The relationship of digestive motor derangements and symptoms in functional dyspepsia remains, therefore, unsettled. A variety of methodological and conceptual shortcomings characterize many of the studies investigating the relationship between gastrointestinal motility disorders and dyspeptic symptoms, and this obviously contributes to a higher level of uncertainty in the field. Recent reports suggest that gastrointestinal dysmotility is associated with perception of some dyspeptic symptoms, at least in a subset of patients. Well-conducted studies using appropriate methodology are needed to verify whether gastrointestinal motor disorders play a causal role in functional dyspepsia and whether this is of clinical relevance.

Effect of alosetron on responses to colonic distension in patients with irritable bowel syndrome

BACKGROUND

Visceral hypersensitivity plays a major role in the pathophysiology of irritable bowel syndrome, as shown by balloon distension studies. 5-HT3 receptors on afferent nerves may modulate visceral sensitivity and be the target of new treatments for irritable bowel syndrome.

AIM

To evaluate the effects of alosetron, a potent and selective 5-HT3 antagonist, on the perception of colonic distension by patients with irritable bowel syndrome, and on the colonic compliance to distension with a barostat.

METHODS

Twenty-five irritable bowel syndrome patients were included in a randomized double-blind parallel group trial; data were available for 22 (Rome criteria; 48 +/- 11 years: 13 men and nine women). Patients were treated for 7 days with placebo (n = 6), alosetron 0.25 mg b.d. (n = 8) or alosetron 4 mg b.d. (n = 8). On day 6, a barostat bag was placed in the left colon. On day 7, after an overnight fast, isobaric phasic distensions were performed (4 mmHg steps, 5 min) up to the step triggering a sensation of abdominal pain.

RESULTS

Groups were comparable at inclusion (age, sex, symptoms, bowel habits). There were no differences between treatment groups in pressure recorded within the bag at the time of first sensation of abdominal pain. However, bag volumes were significantly increased. At the first sensation threshold, median volume differences of 61 mL and 90 mL (P = 0.028) were recorded with alosetron 0.25 mg b.d. and 4 mg b.d., respectively. At the threshold of abdominal pain, these differences were 71 mL (P = 0.039) and 84 mL (P = 0.017). Colonic compliance increased from 5.9 mL/mmHg on placebo to 7.6 mL/mmHg on alosetron 0.25 mg b.d. and to 9.8 mL/mmHg (P = 0.034) on alosetron 4 mg b.d.

CONCLUSION

Alosetron increases the compliance of the colon to distension, and could thereby contribute to changes in perception of colonic distension and improvement in the symptoms of irritable bowel syndrome.

Symptom relief with amitriptyline in the irritable bowel syndrome

Anti-depressants have been reported to be useful in the management of the Irritable Bowel syndrome. We studied the efficacy of amitriptyline for 12 weeks in a randomized double-blind placebo-controlled trial. Forty patients who met predefined criteria entered the trial. They received 25 mg amitriptyline for the first week, 50 mg for the second week and 75 mg nightly thereafter until the end of the 12th week. The drug and placebo groups were comparable in all major pretreatment variables. Amitriptyline was found to be significantly more effective than placebo in producing global improvement, increasing feelings of well-being, reducing abdominal pain and increasing satisfaction with bowel movements. Younger age and increasing extroversion predicted a better response to amitriptyline. Severity of depressive and anxiety symptoms and other personality variables did not influence outcome.

A one-hour active coping stressor reduces small bowel transit time in healthy young adults

OBJECTIVE

To examine the effect of a prolonged active coping stressor on the transit of a substance from the mouth through small intestine in normal human volunteers.

METHOD

Twelve healthy undergraduate males were administered 10 g of the nonabsorbable carbohydrate lactulose in two experimental sessions. In normal individuals, lactulose produces hydrogen gas upon exposure to bacteria residing in the colon. Repeated measurements of breath hydrogen were obtained for 2 hours. In one session, subjects rested quietly for the 2-hour period. In the other counterbalanced session, subjects avoided mild electric shocks by playing videogames for the first hour.

RESULTS

Stress produced a statistically and clinically significant reduction in mean transit time, from 79 to 55 minutes. The magnitude of stress-induced reduction in small bowel transit time was significantly correlated with change in an index of cardiac sympathetic activity, pulse transit time.

CONCLUSIONS

A prolonged active coping stressor with minimal motor requirements produced a decrease in small bowel transit time comparable with that observed in several studies of the effects of physical exercise and in comparisons between normal controls and patients with diarrhea-predominant irritable bowel syndrome.

Review article: irritable bowel syndrome

Irritable bowel syndrome is a disease that can be diagnosed positively on the basis of an established series of criteria and limited exclusion of organic disease. It is the most common disease diagnosed by gastroenterologists and affects about 20% of all people at any one time. Symptoms fluctuate, and the overall prevalence rate is relatively constant in Western communities. Ten per cent of patients present to their physicians; the illness has a large economic impact on health-care utilization and absenteeism. Irritable bowel syndrome is a biopsychosocial disorder in which three major mechanisms interact: psychosocial factors; altered motility; and/or sensory function of the intestine. Management of patients is based on positive diagnosis of the symptom complex, limited exclusion of underlying organic disease and institution of a therapeutic trial. If patient symptoms are intractable, further investigations are needed to exclude significant motility or other disorders. Symptomatic treatment includes fibre for constipation, loperamide for diarrhoea and low-dose antidepressants or infrequent use of antispasmodics for pain; novel pharmacological agents, psychotherapy and hypnotherapy are being evaluated.

Oxytocin increases thresholds of colonic visceral perception in patients with irritable bowel syndrome

AIM

The effects of oxytocin on colonic perception of intraluminal distension were evaluated in 26 patients with irritable bowel syndrome (IBS), using a flaccid bag placed in the descending colon and connected to a computerised barostat.

METHOD

Symptomatic responses (first sensation and pain) were evaluated during isobaric distensions (4 mm Hg increments, five minute duration, five minute interval with return to zero pressure between each step), performed automatically by the barostat, during a continuous infusion of placebo or various doses of oxytocin (10, 20, 30, and 50 mU/min).

RESULTS

The distension pressure (mean (SD)) required to induce a first abdominal sensation was 17.3 (5.5) mm Hg on placebo, 19.9 (5.8) on oxytocin 10 mU/min (NS), 22.3 (6.0) mm Hg on oxytocin 20 mU/min (p < 0.01), 23.1 (6.6) mm Hg on oxytocin 30 mU/min (p < 0.01), and 24.0 (7.1) mm Hg on oxytocin 50 mU/min (p < 0.01). The distension pressure required to induce pain was 24.8 (6.3) mm Hg on placebo, 26.0 (5.8) on oxytocin 10 mU/min (NS), 33.3 (7.8) mm Hg on oxytocin 20 mU/min (p < 0.01), 34.2 (7.6) mm Hg on oxytocin 30 mU/min (p < 0.01), and 34.3 (7.9) mm Hg on oxytocin 50 mU/ min (p < 0.01). Compliance curves were not different after placebo and oxytocin injection at the different doses. Naloxone did not inhibit the effect of oxytocin. Oxytocin also did not alter somatic perception, characterised by the RIII reflex at the level of the biceps femori.

CONCLUSIONS

Oxytocin significantly increases thresholds for visceral perception in IBS patients at doses equal or to greater than 20 mU/min, possibly by acting at the level of visceral afferents.

Autonomic control of colonic tone and the cold pressore test

BACKGROUND

Cardiovascular responses to cold stimulation are well characterised. It is unclear, however, whether cold pain stimulates responses in colonic tone in the transverse and sigmoid regions.

AIMS

To assess the effects of cold stimulation on tone nd motility in the transverse and sigmoid colon and on cardiovascular autonomic activity.

METHODS

Phasic and tonic motility of the transverse and sigmoid colon, pulse rate, and beat to beat pulse variability (which are measures of centrally mediated changes in autonomic function) were measured before, during, and after a standard cold pressor test in 22 healthy volunteers.

RESULTS

Cold pain induced a significant increase in colonic tone but not phasic contractility in the transverse and sigmoid regions. Simultaneously, cold pain increased pulse interval variability.

CONCLUSION

The findings are consistent with the hypotheses that cold pain produces coactivation of both the sympathetic and parasympathetic limbs of the autonomic nervous system and that cold induced changes in colonic tone are temporally associated with alterations in central autonomic nervous activity.

Gastric and small intestinal motility in health and disease

Although symptoms possibly related to motor dysfunction appear to be common, primary disorders of the foregut motor apparatus, defined on the basis of a discrete myoneural pathology, are notably rare. This phenomenon may as much reflect the relatively primitive nature of diagnostic methods as the true rarity of such disorders. Although diagnostic methodologies increase in sophistication and availability, their clinical impact has been limited by an imperfect relationship between symptoms and dysfunction and by a relatively poor ability of such tests to predict response to available therapeutic strategies. An ever-increasing understanding of the complex, often interrelated motor and sensory phenomena that contribute to symptoms, together with the development of consensus on the use and interpretation of motility tests and the more widespread application of sophisticated histologic, immunologic, biochemical, and molecular biologic methodologies to the study of these disorders, should lead, in the years to come, to much needed progress in this area.

Hyperventilation, central autonomic control, and colonic tone in humans

Symptoms attributable to hyperventilation are common among patients with the irritable bowel syndrome (IBS); indeed, some have suggested that hyperventilation may exacerbate the alimentary symptoms of IBS. Hyperventilation changes haemodynamic function through central and peripheral mechanisms; its effects on colonic motor function, however, are unknown. The aim of this study, therefore, was to assess the effects of hyperventilation on colonic tone and motility and on cardiovascular autonomic activity, and to discover if hypocapnia was critical to elicit the response. Phasic and tonic motility of the transverse and sigmoid colon, end tidal PCO2, pulse rate, and beat to beat pulse variability were assessed before, during, and after a five minute period of hypocapnic hyperventilation in 15 healthy volunteers; in seven other subjects, effects of both eucapnic and hypocapnic hyperventilation were evaluated. Hypocapnic but not eucapnic hyperventilation produced an increase in colonic tone and phasic contractility in the transverse and sigmoid regions and an increase in pulse rate and pulse interval variability. The findings are consistent with inhibition of sympathetic innervation to the colon or direct effects of hypocapnia on colonic smooth muscle, or both. These physiological gut responses suggest that some of the changes in colonic function are caused by altered brain or autonomic control mechanisms.

Overinterpretation of gastroduodenal motility studies: two cases involving Munchausen syndrome by proxy

Two children were thought to have an atypical gastroduodenal motility disorder because of the history and clinical course; both had received parenteral alimentation because of claims of inability to tolerate enteral feedings, and both continued to have unusual medical problems during parenteral alimentation. Both children had motility studies that were interpreted by a pediatric gastroenterologist to be "abnormal" and "diagnostic" of a motility disorder, but each was eventually shown to have a behavioral abnormality related to Munchausen syndrome by proxy.

Irritable bowel syndrome. Managing the patient with abdominal pain and altered bowel habits

Irritable bowel syndrome is a common complex of syndromes thought to be generated by a motility or sensory disturbance of the gastrointestinal tract. It is a frequent cause of chronic abdominal pain and altered bowel habits. Patients who seek medical attention for irritable bowel syndrome often do so because of psychosocial factors. Therapy remains largely empirical, directed toward the relief of symptoms in the context of a supportive physician-patient relationship.

Sleep and duodenal motor activity in patients with severe non-ulcer dyspepsia

The prevalence of sleep disturbances was studied in patients with severe non-ulcer dyspepsia. It was also considered if the change in sleep pattern was associated with changes in the rhythmic fasting motor activity of the gastrointestinal tract, and if motor events correlate with the patient's symptoms. Motor activity in the duodenum was monitored over a 24 hour period under freely ambulatory conditions in 10 healthy controls and in 10 patients with severe non-ulcer dyspepsia using a transnasally placed catheter with six solid state pressure transducers connected to a digital data logging device. Symptoms and sleep disturbance were assessed by questionnaire and diary. Based on their symptoms, the patients were separated into two groups: those with dyspepsia symptoms only (non-ulcer dyspepsia; n = 5) and those with dyspepsia and additional functional symptoms thought to arise from the lower gastrointestinal tract (non-ulcer dyspepsia+irritable bowel syndrome; n = 5). When compared with either the control or the non-ulcer dyspepsia+irritable bowel syndrome group, non-ulcer dyspepsia patients had a considerably decreased number of migrating motor complexes during the nocturnal period (0.7 v 4.6), a decreased percentage of nocturnal phase I (5.2% v 78.0%), and an increased percentage of the nocturnal period in phase II (94% v 15.4%). Patients with non-ulcer dyspepsia+irritable bowel syndrome were not different from normal controls. Four of the non-ulcer dyspepsia patients and all of the non-ulcer dyspepsia+irritable bowel syndrome patients reported difficulties with sleep. Clusters of high amplitude tonic and phasic activity, not accompanied by subjective reports of discomfort were noted in several patients in both groups during the study. In eight of 10 patients, abdominal pain was reported during normal motor activity, while in one patient, pain correlated with phase III of the migrating motor complex. In contrast with previous reports in patients with irritable bowel syndrome, our findings suggest an abnormality of diurnal rhythmicity--shown in changed sleep and changed rhythmic duodenal motor activity--in patients with chronic abdominal pain thought to arise from the upper gastrointestinal tract.

Predominant symptoms in irritable bowel syndrome correlate with specific autonomic nervous system abnormalities

BACKGROUND/AIMS

Irritable bowel syndrome may be influenced by the autonomic nervous system. Abnormalities in autonomic function, colon transit time, and psychological profiles in 21 patients were assessed.

METHODS

Using modified Manning criteria for irritable bowel syndrome, patients were classified as constipation-predominant or diarrhea-predominant. Autonomic function was determined by one vagal cholinergic and two sympathetic adrenergic measures. Colon transit was assessed by radiopaque markers, and psychological profiles were determined by three inventories.

RESULTS

Autonomic function tests showed that diarrhea-predominant subgroup values for one sympathetic adrenergic measure (postural adjustment ratio) were significantly different from controls (P < 0.01). Constipation-predominant subgroup values were significantly lower for the vagal cholinergic measure R-R interval (P < 0.05). Colon transit measures differed by subgroup in left, right, rectosigmoid, and total colon transit times. Both subgroups differed significantly from controls on psychological measures; the constipation subgroup showed more psychological distress.

CONCLUSIONS

Irritable bowel syndrome specific-symptom subgroups had different patterns of autonomic functioning, colonic transit, and psychological measures. The constipation subgroup is associated with a cholinergic abnormality and the diarrhea-predominant subgroup with an adrenergic abnormality. These findings suggest specific associations between the autonomic nervous system, predominant physical symptoms, colon transit time, and psychological factors in patients with irritable bowel syndrome.

Evaluation of colonic sensory thresholds in IBS patients using a barostat. Definition of optimal conditions and comparison with healthy subjects

To study the role of abnormal visceral perception in the pathophysiology of the irritable bowel syndrome (IBS), we evaluated colonic tone and visceral perception during intracolonic distension using a flaccid balloon connected to a computerized barostat and placed in the descending colon of IBS patients and healthy controls. In the first part of the study, basal colonic tone and response to pharmacological (neostigmine and glucagon) and physiological (1000-kcal meal) stimuli were recorded in nine IBS patients. Colonic tone increased by 72 +/- 27% after injection of neostigmine and decreased by 88 +/- 62% after glucagon. After the meal, the maximal increase in colonic tone was 76 +/- 31% with the total response to the meal lasting 109.7 +/- 32.0 min. In the second part of the study, symptomatic responses (discomfort and pain thresholds) and pressure variations were evaluated during two different methods of distension (stepwise and intermittent) in a randomized order in the nine IBS patients and six healthy controls. Each distension method was repeated twice in IBS patients to study reproducibility. In IBS patients, the mean discomfort threshold volume was 172 +/- 76 ml when using stepwise and 167 +/- 43 ml when using intermittent distension. The mean pain threshold volume was 250 +/- 25 ml when using stepwise and 211 +/- 22 ml when using intermittent distension, this difference being statistically significant (P < 0.02). Discomfort and pain threshold volumes recorded during the first session of the same distension method were not different from those recorded during the second one.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-alimentary aspects of the irritable bowel syndrome

The irritable bowel syndrome (IBS) is characterized by alimentary and non-alimentary symptoms; the aim of this study was to assess the clinical value and discriminant function of non-alimentary symptoms in the irritable bowel syndrome. Alimentary and non-alimentary symptoms, estimated daily dietary fibre intakes, ability to express personal feelings, anxiety and depression ratings, and life events and difficulties inventories were compared in 128 hospital out-patients with IBS and 113 age and sex matched control subjects not seeking health care, randomly recruited from the community. Alimentary symptoms correlated closely with those non-alimentary symptoms often associated with the hyperventilation syndromes, difficulties in expressing personal feelings and anxiety, and depression ratings. Life events and difficulties, and estimated daily dietary fibre intakes did not differ significantly between patients and controls. With the exception of abdominal bloating, no significant gender differences were observed in IBS symptoms in either the IBS or control groups. The irritable bowel syndrome is one facet of a more general condition of illness behaviour which includes the hyperventilation syndrome and an inassertiveness in expressing personal feelings. Though non-alimentary symptoms did not improve diagnostic accuracy beyond that achieved by a combination of alimentary symptoms, their recognition provides alternative approaches to the management of refractory IBS.

The role of psychological factors in gastrointestinal conditions. A review pertinent to DSM-IV

The authors reviewed the literature to assess the relationship between psychological factors and gastrointestinal conditions. The conditions that were found to be more relevant and worthy of future investigation were nonulcerative dyspepsia, inflammatory bowel disease (regional enteritis), and irritable bowel syndrome. The pertinent findings suggest that an important link exists between psychological factors and gastroenterological disorders, which supports the need for modification of the DSM-III-R's diagnostic category, "Psychological Factors Affecting Physical Condition." In concert with a subcommittee addressing other organ systems and psychological factors, the authors conclude that a diagnostic approach with greater utility would be useful for both researchers and clinicians. A conceptual framework as proposed in DSM-IV could also advance knowledge of psychological factors and their contribution or role in the etiology, perpetuation, and exacerbation of certain gastrointestinal conditions.

Provocation testing in noncardiac chest pain

The ability to reproduce chest pain and to identify the esophagus as the source of this pain are the major reasons why provocation testing has become standard in the evaluation of patients with noncardiac chest pain. Recent studies that challenge the validity of performing provocation tests have polarized experts into two camps: those who would abandon such testing because of its low sensitivity and low specificity, and those who would use testing judiciously because of moderate increases in diagnostic yield. Use of 24-hour pH and pressure testing has shown a high number of chest pain events associated with acid reflux in patients with positive cholinergic stimulation tests and esophageal dysmotility, as well as pain with esophageal dysmotility in patients with positive acid infusion tests. Mechanisms of esophageal chest pain are not known. All provocation agents can decrease coronary flow reserve (i.e., induce microvascular angina), thus raising the question of a cardiac source of pain even in patients with positive presumed esophageal provocation. Acid infusion, cholinergic stimulation, and balloon distention are discussed in light of 24-hour pH and pressure monitoring. Esophageal distention and the role of acid in inducing chest pain are emphasized. The role of stress, the use of defined stressors to induce chest pain, and altered pain perception as a final common pathway for chest pain are examined.

Transit through the proximal colon influences stool weight in the irritable bowel syndrome

The inherent variability of symptoms and motor abnormalities in patients with the irritable bowel syndrome has hampered the demonstration of motor abnormalities that could underlie symptoms. The aim in the current study was to evaluate whether altered regional capacitance or transit of solid residue through the unprepared human gut were factors in the diarrhea of patients with the irritable bowel syndrome. In 10 such patients and in 5 healthy controls, gastric and small bowel transits were evaluated scintigraphically by means of a mixed meal containing 99mTc-labeled resin pellets. Regional colonic transit was quantitated by 111In-labeled pellets delivered to the ileocecal region by a pH-sensitive, methacrylate-coated capsule. Symptomatic patients did not have significantly altered gastric or small bowel transits, but colonic transit was accelerated in 7 of 10 persons with the irritable bowel syndrome (P less than 0.02), in the proximal colon of five patients and in the left colon of two patients. The 24-hour stool weight was positively correlated with the rate at which solid residue emptied from the ascending and transverse colons (r = 0.78; P less than 0.01). There was also an inverse relationship between emptying rates and maximal volumes accommodated by the proximal colon (r = -0.58; P less than 0.05), although the maximum volume of the proximal colon was not significantly different in patients and healthy subjects. Thus, accelerated transit through the proximal colon is a factor in the pathophysiology of the irritable bowel syndrome and influences the stool weight of such patients. The capacitance of the proximal colon presumably influences its storage capacity and, hence, the rate at which it empties.

Antroduodenal manometry. Usefulness and limitations as an outpatient study

We performed fasting and postprandial recordings of antroduodenal manometry in 21 normal volunteers, 13 patients with insulin-dependent diabetes mellitus and gastrointestinal symptoms, and 11 patients with the irritable bowel syndrome. None of the patients or volunteers had previously undergone an intestinal intubation study. Recordings could not be obtained from four of the diabetic patients due to failure to intubate the pylorus. Catheter migration led to incomplete antral data in a further 21% of all recordings. Due to the wide variations demonstrated by the normal volunteers, parameters of either the migrating motor complex (MMC) or the fed response could not differentiate between either of the patient groups and/or the controls. Similarly, while abnormal patterns of either fasting or postprandial motility were common in the diabetic patients, manometry had a sensitivity of only 67% in comparison to the less invasive radionuclide gastric emptying study. Furthermore, manometry failed to identify any diagnostic abnormality in irritable bowel patients; in particular, the incidence of "clustered" contractions was similar in all three groups. We conclude that short duration antroduodenal manometry is of limited diagnostic usefulness due to the difficulties in pyloric intubation in the presence of a dilated stomach and the intrinsic variability in normal motor patterns, perhaps excerbated by the stressful effects of the procedure itself in tube-naive subjects.

Non-ulcer dyspepsia

This paper discusses the definition of non-ulcer dyspepsia and its relationship to other functional bowel disorders. The research on the prevalence, outcome, aetiology and management of this condition is reviewed with particular emphasis on its multifactorial nature. Future research will need to concentrate on the inter-relationship of physical and psychosocial factors including the health beliefs of the individual patient.

Role of visceral afferent mechanisms in functional bowel disorders

This report analyzes the clinical and physiological evidence supporting a role for altered visceral afferent mechanisms in the pathogenesis of two functional bowel syndromes: noncardiac chest pain and the irritable bowel syndrome. Considerable recent evidence indicates that increased contractility is present only in a minority of patients and that hypercontractile episodes are not temporally related to abdominal pain. In contrast, altered sensation and motor reflexes in response to physiological stimuli, such as mechanical distention or acid, is common when appropriately investigated. The vagal and spinal afferent innervation mediates visceral sensation and is involved in multiple reflex loops regulating gastrointestinal effector function, such as motility and secretion. Sensory input can be modulated peripherally at the afferent nerve terminal, at the level of prevertebral ganglia, the spinal cord, and the brainstem. An up-regulation of afferent mechanisms would result both in altered conscious perception of physiological stimuli and in altered motor reflexes. Current evidence is consistent with an alteration in the peripheral functioning of visceral afferents and/or in the central processing of afferent information in the etiology of altered somatovisceral sensation and motor function observed in patients with functional bowel disease.