Effects of Antidepressants on Gastric Function in Patients with Functional Dyspepsia

BACKGROUND

Functional dyspepsia (FD) is a highly prevalent functional bowel disorder. The effects of antidepressant therapy (ADTx) on gastric sensorimotor function in FD patients are poorly understood.

AIMS

Determine whether FD and subtypes with abnormalities in gastric function respond differently to ADTx compared to those with normal physiology.

METHODS

This multicenter, prospective trial randomized FD patients to 12 weeks of amitriptyline (AMI; 50 mg), escitalopram (ESC; 10 mg), or matching placebo. Demographics, symptoms, psychological distress, gastric emptying, and satiation were measured. Gastric accommodation (GA) using single-photon emission computed tomography imaging was performed in a subset of patients. An intent to treat analysis included all randomized subjects. The effect of treatment on gastric emptying was assessed using ANCOVA. A post hoc appraisal of the data was performed categorizing patients according to the Rome III subgrouping (PDS and EPS).

RESULTS

In total, 292 subjects were randomized; mean age=44 yrs. 21% had delayed gastric emptying. Neither antidepressant altered gastric emptying, even in those with baseline delayed gastric emptying. GA increased with ADTx (P=0.02). Neither antidepressant affected the maximal-tolerated volume (MTV) of the nutrient drink test although aggregate symptom scores improved compared to placebo (P=0.04). Patients with the combined EPS-PDS subtype (48%) had a lower MTV on the nutrient drink test compared to the EPS group at baseline (P=0.02). Postprandial bloating improved with both AMI (P=0.03) and ESC (P=0.02).

CONCLUSIONS

Amitriptyline (50 mg) improves FD symptoms but does not delay gastric emptying, even in patients with baseline delayed gastric emptying. GA improved with low-dose ADTx; the precise mechanism of action is unknown warranting further study.

A single-center, prospective, double-blind, sham-controlled, randomized study of the effect of a vibrating capsule on colonic transit in patients with chronic constipation

BACKGROUND

In an open-label study of 26 patients with IBS-C and chronic constipation, treatment with a vibrating (VIBRANT) capsule twice a week for 7.5 weeks resulted in 88.5% responders. Effects on colonic transit are unclear. We aimed to compare effects of VIBRANT and sham capsule treatment on colonic transit in patients with functional constipation.

METHODS

Patients with functional constipation (Rome III criteria) were randomized to VIBRANT or sham capsule treatment for 8 weeks and underwent scintigraphic colonic transit measurements during week 8. We estimated the overall rate of colonic transit from the slope of progression of colonic geometric center over 48 hours. The capsule was activated 8 hours after ingestion, and the vibration sequence included 240 cycles.

KEY RESULTS

There were no significant group differences in overall colonic transit [GC48, 2.76 (IQR 2.42-4.03) for sham group and 3.46 (2.55-4.61) for active treatment group (P=.13)]. Additionally, the progression of the isotope through the colon was numerically faster, though not significantly different (slope, P=.14) in the VIBRANT capsule group compared to the sham group. Three participants in the VIBRANT capsule group had accelerated colonic transit at 32 hours and faster colonic transit slope compared to the 95th percentile of the sham group.

CONCLUSIONS AND INFERENCES

Although there were no group differences between VIBRANT and sham capsule treatment on colonic transit, at least one (and possibly three) of 12 patients receiving the VIBRANT capsule had faster colonic transit. The vibration parameters to accelerate colonic transit in patients with functional constipation require further optimization.

Opioid analgesic use among patients presenting with acute abdominal pain and factors associated with surgical diagnoses

BACKGROUND

The prevalence of chronic opioid use among non-cancer patients presenting with acute abdominal pain (AAP) is unknown. The aim was to characterize opioid use, constipation, diagnoses, and risk factors for surgical diagnoses among non-cancer patients presenting with AAP to an emergency department (ED).

METHODS

We performed a retrospective, observational cohort study of all (n=16,121) adult patients (88% from MN, IA and WI) presenting during 2014 with AAP. We used electronic medical records, and focused on 2352 adults with AAP who underwent abdominal CT scan within 24 hours of presentation. We determined odds ratios of association with constipation and features predicting conditions that may require surgery (surgical diagnosis).

KEY RESULTS

There were 2352 eligible patients; 18.8% were opioid users. Constipation was more frequent in opioid (35.1%) compared to non-opioid users [OR 2.88 (95% CI 2.28, 3.62)]. Prevalence of surgical diagnosis in the opioid and non-opioid users was 35.3% and 41.7% respectively (P=.019). By univariate analysis, age and neutrophil count independently predicted increased risk, and chronic opioid use decreased risk of surgical diagnosis. Internal validation of logistic models using a randomly selected validation subset (25% of entire cohort, 587/2352) showed receiver operating characteristic (ROC) curves for the validation and full cohorts were similar.

CONCLUSIONS AND INFERENCES

Approximately 19% of adults presenting with AAP were opioid users; constipation is almost three times as likely in opioid users compared to non-opioid users presenting with AAP. Factors significantly associated with altered risk of surgical diagnoses were age, opioid use, and neutrophil count.

Irritable bowel syndrome and the perinatal period: lower birth weight increases the risk

BACKGROUND

Early life events have been found to be associated with irritable bowel syndrome (IBS) suggesting a role in development of functional disorders. The study aim was to identify potential perinatal risk factors for adult IBS.

METHODS

Utilizing a population-based nested case-control design, cases who met modified Rome III criteria for IBS and age- and-gender matched controls were identified using responses from prior mailed surveys to a random sample of Olmsted County residents. Medical records of eligible respondents were reviewed for perinatal events of interest. The association of early life events with subsequent case status was assessed using conditional logistic regression.

KEY RESULTS

Of 3 417 respondents, 513 were born in Olmsted County and 108 met criteria for IBS. Due to missing records, 89 pairs were included in the final analyses. Logistic regression revealed only birth weight as a predictor of IBS. Lower birth weight increased the odds for IBS (OR = 1.54 [95% CI = (1.12, 2.08), p = 0.008]). Median birth weight was 3.35 kg (range: 1.96-5.24) and 3.57 kg (range: 2.18-4.59) for cases and controls, respectively. Maternal age, delivery method, and antibiotic exposure were not associated with IBS status but this study was only powered to detect large odds ratios.

CONCLUSIONS AND INFERENCES

Lower birth weight was observed as a risk factor for IBS. It is not clear if in utero developmental delays directly lead to IBS or if low birth weight is a prospective marker for subsequent early life problems leading to IBS.

Supraesophageal Reflux: Validation of a Symptom Questionnaire

OBJECTIVES: To develop and validate a questionnaire for supraesophageal manifestations of reflux (SER) that will facilitate its study in clinical and research settings.

STUDY DESIGN: The Supraesophageal Reflux Questionnaire (SERQ) and previously validated Reflux Symptom Index (RSI) were subjected to multiple types of validity testing, including content validity, concurrent validity, reproducibility, and predictive validity.

RESULTS: The concurrent validity and reproducibility of both instruments was good to excellent for most items tested. The predictive validity of the SERQ was superior to the RSI when it included the covariates of history of sinusitis, use of over-the-counter antacid medications, age, gender, and body mass index.

CONCLUSIONS: The SERQ will serve as both a useful clinical and research tool by offering not only SER symptom information, like the RSI, but also information about the patient's medical history and medication usage that will facilitate use of the SERQ in research protocols.

EBM rating: B-2b

Overdiagnosis of gastro-esophageal reflux disease and underdiagnosis of functional dyspepsia in a USA community

BACKGROUND

There is symptom overlap between gastro-esophageal reflux disease (GERD) and functional dyspepsia (FD). We aimed to test the hypothesis that FD cases are now more likely mislabeled as GERD.

METHODS

In subjects from Olmsted County, MN seen at Mayo Clinic: (i) Investigation of GERD and FD diagnosis rates between 1985 and 2009. (ii) Assessment of survey-based upper gastrointestinal symptoms between 1988 and 2009. (iii) Analysis of patients reporting GERD and/or FD symptoms and subsequently receiving a consistent diagnosis of GERD and/or FD during a medical encounter. (iv) Assess the association between PPI use and GERD and/or FD symptoms and between actual diagnoses received.

KEY RESULTS

(i) Yearly GERD diagnosis rates rose between 1985 and 2009 (325-1866 per 100 000). FD diagnosis rates rose from 45 in 1985, to 964 in 1999 but decreased to 452 per 100 000 in 2009. (ii) Reported GERD symptoms did not significantly change between three survey waves in the years 1988-2009 (p = 0.052), whereas FD symptoms slightly increased (p = 0.01). (iii) 62.9% of subjects reporting GERD symptoms received a GERD diagnosis, however only 12.5% of subjects reporting FD symptoms received a FD diagnosis. (iv) PPI use was associated with documented GERD diagnosis (p < 0.001), however there was no significant association between GERD symptoms and PPI use (p = 0.078).

CONCLUSIONS & INFERENCES

We have found evidence supporting a systematic bias away from diagnosing FD, favoring a GERD diagnosis.

Novel partial 5HT3 agonist pumosetrag reduces acid reflux events in uninvestigated GERD patients after a standard refluxogenic meal: a randomized, double-blind, placebo-controlled pharmacodynamic study

BACKGROUND

Low basal lower esophageal sphincter (LES) pressure and transient LES relaxations are major causes of gastroesophageal reflux disease (GERD). Pumosetrag, a novel selective partial 5HT3 receptor agonist, showed a promising effect on reducing reflux events in health. We aimed to evaluate the effect of pumosetrag on changes in reflux episodes, lower esophageal sphincter pressure (LESP), and specific symptoms in patients with GERD receiving a refluxogenic meal.

METHODS

Patients with GERD, who developed heartburn and/or regurgitation after ingestion of a refluxogenic meal, were randomized to 1 of 3 dose levels of pumosetrag (0.2, 0.5, or 0.8 mg) or placebo. Before and after 7 days of treatment, patients underwent manometry, intraesophageal multichannel, intraluminal impedance and pH after a standard refluxogenic meal.

KEY RESULTS

A total of 223 patients with GERD [125 (56%) women, mean (SD) age = 36 (12) years] were enrolled. No overall treatment effects were detected for the total number of reflux episodes (acidic and weakly acidic) (p > 0.5); however, significant treatment effects (p < 0.05) on the number of acid reflux episodes were observed with lower values on pumosetrag 0.2 mg (10.8 ± 1.1), 0.5 mg (9.5 ± 1.1), and 0.8 mg (9.9 ± 1.1) compared with placebo (13.3 ± 1.1). Significant treatment effects (p < 0.05) were also observed for the percentage of time pH was <4, with less time for pumosetrag at 0.5 mg (10%) and 0.8 mg (10%) compared with placebo (16%).

CONCLUSIONS & INFERENCES

In GERD, the partial 5HT3 agonist pumosetrag significantly reduced the rate of acid reflux events but did not result in a significant change in LESP or symptomatic improvement over a 1-week treatment period.

Prevalence of colonic motor or evacuation disorders in patients presenting with chronic nausea and vomiting evaluated by a single gastroenterologist in a tertiary referral practice

BACKGROUND

Nausea and vomiting are thought to result from upper gastrointestinal dysfunctions. Our clinical observations led to the hypothesis that colonic motor dysfunction is associated with nausea and vomiting.

METHODS

We reviewed electronic medical records (EMR) of 149 patients presenting with complaints of nausea and/or vomiting in a tertiary gastroenterology practice to investigate the association with disorders of colonic motor or evacuation disorders. We extracted demographics, gastric emptying (GE in 149) and colonic transit (CT in 138) of solids, ascending colon emptying half-time (AC t1/2 ), rectal evacuation by anorectal manometry (ARM) in 91 and balloon expulsion test (BE) in 55 patients. We estimated the proportions with delayed GE or CT, based on the 5th percentile of GE (in 319) and CT in 220 healthy volunteers using same method.

KEY RESULTS

Among 11 patients with nausea and/or vomiting with only GE measured, five had delayed and six normal GE. Among the 149 patients, 77 (52%) patients had evacuation disorders, confirmed by objective tests in 68 patients, and clinical examination in nine patients. In the 138 patients with both GE and CT measured, 106 (76%) had both normal GE and CT, 11 (8%) only delayed GE, 16 (11%) normal GE with delayed CT, and five (3%) delayed GE and CT. Among 21 patients (15%) with delayed CT, nine had slow AC t1/2 and 12 evacuation disorder.

CONCLUSIONS & INFERENCES

In patients with chronic nausea and/or vomiting in gastroenterology practice, evaluation of colonic motility and rectal evacuation should be considered, since about half the patients have abnormal functions that conceivably contribute to the presenting nausea and/or vomiting.

Randomised clinical trial: the effects of daikenchuto, TU-100, on gastrointestinal and colonic transit, anorectal and bowel function in female patients with functional constipation

BACKGROUND

Daikenchuto, a Japanese herbal medicine used for post-operative ileus and constipation, dose dependently stimulates gastrointestinal (GI) motility and decreases rectal compliance and sensation. Effects of TU-100 (commercial form of daikenchuto) in adults with constipation are unknown.

AIM

To compare the effects of oral TU-100, 2.5 g t.d.s. or 5 g t.d.s. and placebo t.d.s. on GI and colonic transit (CT), rectal compliance (RC) and sensation thresholds (RST), anal sphincter pressures (ASP) and bowel function in female patients with functional constipation (FC).

METHODS

We conducted a single-centre, randomised, parallel-group, double-blind, pharmacodynamic study; 45 female patients with FC without evidence of rectal evacuation disorder were assigned to 28 days' treatment with oral placebo or TU-100 (Tsumura USA, Princeton, NJ, USA). Demographic data and CT were measured at baseline and randomisation stratified by baseline CT (GC> or <1.9) and by BMI (<25 or ≥25 kg/m(2) ). At the end of treatment period, we measured GI and CT by scintigraphy, RST and RC by barostat, ASP by manometry, psychosensory sensations, bowel function by daily diary and quality of life (QOL). The study had power to detect effect sizes of 33% (CT), 40% (RC) and 46% (RST). Statistical analysis included BMI as covariate.

RESULTS

TU-100 had no significant effects on GI or CT, RC, ASP, recto-anal pressure difference, or RST. The 5 g t.d.s./day dose was associated with lower RST for first sensation and gas (unadjusted P: 0.045 and 0.024 respectively). There were no treatment effects on psychosensory symptoms, stool frequency, stool consistency or QOL.

CONCLUSION

Mechanisms underlying the observed clinical benefit of TU-100 remain unclear (ClinicalTrials.gov NCT01139216).

Natalizumab for moderate to severe Crohn's disease in clinical practice: the Mayo Clinic Rochester experience

BACKGROUND

Not all patients with Crohn's disease (CD) respond or maintain response to anti-tumor necrosis factor (TNF) agents and alternative treatment is necessary. Natalizumab, a monoclonal antibody to alpha-4 integrin approved for CD, has demonstrated efficacy in randomized clinical trials. We describe our experience with natalizumab in clinical practice at Mayo Clinic Rochester.

METHODS

Consecutive patients prescribed natalizumab for active CD were invited to participate and were followed prospectively. Incidence of infection, hospitalization, neoplasm, or other adverse events were recorded. Clinical activity was assessed using the Harvey-Bradshaw Index at each 30-day infusion visit.

RESULTS

Between April 2008 and September 2010, 36 patients were prescribed natalizumab and 30 (83.3%) agreed to participate. Median disease duration was 9 years (range, 3-43). Twenty-three patients had prior exposure to two anti-TNF agents, seven to one agent. All patients experienced at least one adverse event; none of the 13 patients in whom natalizumab was stopped (43%) discontinued due to adverse events. Five patients had infusions held for infection. No patient developed progressive multifocal leukoencephalopathy (PML). Fourteen patients (46%) had clinical response. The cumulative probability of achieving complete response within 1 year was 56% (28%-73%). Four of seven patients were weaned off corticosteroids.

CONCLUSIONS

In our experience with natalizumab in clinical practice, adverse events were manageable and did not result in treatment cessation. No PML cases were seen and clinical response was similar to that in clinical trials. Natalizumab results in clinical benefit in patients who have active disease and have failed anti-TNF therapy.

Comparison of calculations to estimate gastric emptying half-time of solids in humans

BACKGROUND

Measuring solid gastric emptying (GE) at 4 h is used to identify gastroparesis. GE half-time (GE T(1/2) ) is useful to assess overall and early GE.

AIM

To examine the validity of hourly imaging as a measurement of GE T(1/2) compared with estimates from more detailed imaging.

METHODS

155 human subjects (99 female, 56 male) underwent scintigraphic GE of a solid-liquid meal. We calculated the GE T(1/2) using linear interpolation based on a full set of abdominal images obtained over 4 h, and the GE T(1/2) based on images at 1, 2, 3, and 4 after the meal with interpolation of data.

KEY RESULTS

Differences in GE T(1/2) values (entire set of scan times compared with just the hourly scans) were small [overall median (5th, 95th percentiles) = -0.2[-7.5, 4.6] min] with slightly greater differences in males compared with females. The agreement between the two methods was very high [concordance correlation coefficient (CCC) (95% CI) = .993 (0.990, 0.995)] and a Bland-Altman plot indicated the variation in the results between the two methods did not change appreciably across the range of GE studied (within ±10 in for all but four subjects). Calculated GE T(1/2) values, omitting the 3-h data from the hourly measurements, were associated with similar high accuracy overall and for fast GE, but were less accurate with slow GE.

CONCLUSIONS & INFERENCES

sults of GE T(1/2) solids, using hourly imaging over 4 , are accurate in the range 75-235 n which reflects the typical range of GE of solids in health and disease.

Performance characteristics of scintigraphic measurement of gastric emptying of solids in healthy participants

BACKGROUND

Gastric emptying (GE) is measured in pharmacodynamic and diagnostic studies. Our aim was to assess inter- and intra-subject coefficients of variation (COV) of scintigraphic GE measurements in healthy subjects, and associations of GE with gender and body mass index (BMI).

METHODS

Data from participants with scintigraphic measurements of gastric emptying of solids were analyzed. Primary endpoints were gastric emptying T(1/2) (GE T(1/2) ) and GE at 1, 2, 3, and 4 h.

KEY RESULTS

The patient cohort consisted of 105 males and 214 females; at least two studies were performed in 47 subjects [16 males (M), 32 females (F)]. Inter-subject COV (COV(inter) ) for GE T(1/2) were similar in M and F: overall 24.5% (M 26.0%, F 22.5%); COV are predictably lowest for GE at 4 h (COV(inter) 9.6%). COV(intra) for T(1/2) and GE at 4 h were overall 23.8% and 12.6%, and were similar to COV(inter) values. Gender (but not age or BMI) was significantly associated with GE T1/2 [P < 0.001, F 127.6 ± 28.7 (SD) min; M 109.9 ± 28.6 min] and with GE at 1 h and 2 h. Repeat GE T(1/2) values in 47 participants were significantly correlated (r = 0.459, P < 0.001) with median difference of -6 min (mean -1.6, range -56 to 72 min). Bland-Altman plots showed Δ GE T(1/2) similarly distributed across mean GE T(1/2) 100-155 min, and across studies conducted 90-600 days apart.

CONCLUSIONS & INFERENCES

Inter-subject variations in scintigraphic GE results are only slightly higher than the intra-subject measurements, which are also reproducible over time in healthy volunteers. Gender, but not BMI, is significantly associated with GE results.

A randomised, placebo-controlled trial comparing the effects of tapentadol and oxycodone on gastrointestinal and colonic transit in healthy humans

BACKGROUND

Tapentadol is a mu-opioid receptor agonist and norepinephrine reuptake inhibitor. In clinical trials, tapentadol provided somatic pain relief comparable to mu-opioids such as oxycodone, with significantly less gastrointestinal adverse effects. The acute effects of tapentadol on gastrointestinal and colonic transit are unclear.

AIM

To compare acute effects of oral tapentadol and oxycodone on gastric, small bowel and colonic transit of solids in 38 healthy human subjects.

METHODS

In a randomised, parallel-group, double-blind, placebo-controlled study of the effects of identical-appearing tapentadol immediate release (IR), 75 mg t.d.s., or oxycodone IR, 5 mg t.d.s., for 48 h, we measured gastric (GE), small bowel (SBT measured as colonic filling at 6 h) and colonic transit by validated scintigraphy. Drug was commenced on the evening before the start of the transit test. The primary endpoints were overall colonic transit (geometric centre, GC) at 24 h and GE half-time (t1/2 ). ancova of transit data included gender or BMI as covariates. Adverse effects were summarised.

RESULTS

At the doses tested, oxycodone and tapentadol significantly delayed GE t1/2 and SBT, but not overall colonic transit, compared to placebo. Transit profiles in all regions were not significantly different between oxycodone and tapentadol at the doses tested. Both oxycodone and tapentadol were associated with nausea and central effects attributable to central opiate effects.

CONCLUSIONS

Tapentadol significantly delayed gastric emptying t1/2 and small bowel transit, similar to oxycodone. These data suggest that acute administration of tapentadol may not have significant advantages over standard mu-opioids, in terms of the potential to avoid upper gastrointestinal motor dysfunction.

Effects of vaginal hysterectomy on anorectal sensorimotor functions--a prospective study

BACKGROUND

While bowel and bladder dysfunction are recognized consequences of a radical hysterectomy, the effects of a simple hysterectomy on anorectal sensorimotor functions, particularly rectal sensation, vary among studies and the effects on rectal compliance remain unknown. Our aims were to prospectively evaluate anorectal sensorimotor functions before and after a hysterectomy.

METHODS

Anal pressures, rectal compliance, capacity, sensation, and bowel symptoms were assessed before, at 2 months, and at 1 year after a simple vaginal hysterectomy for benign indications in 19 patients. Rectal staircase (0-44 mmHg, 4-mmHg steps), ramp (0-200 mL at 50, 200 and 600 mL min(-1)) and phasic distentions (8, 16, and 24 mmHg above operating pressure) were performed.

KEY RESULTS

Anal resting (63 ± 4 before, 56 ± 4 mmHg after) and squeeze pressures (124 ± 12 before, 124 ± 12 mmHg after), rectal compliance and capacity (285 ± 12 before, 290 ± 11 mL 1 year after), and perception of phasic distentions were not different before vs after a hysterectomy. Sensory thresholds for first sensation and the desire to defecate were also not different, but pressure and volume thresholds for urgency were somewhat greater (Hazard ratio = 0.7, 95% CI [0.5, 1.0]) 1 year after (vs before) a hysterectomy. Rectal pressures were higher (P < 0.0001) during fast compared with slow ramp distention; this rate effect was greater at 1 year after a hysterectomy, particularly at 100 mL (P = 0.04).

CONCLUSIONS & INFERENCES

A simple vaginal hysterectomy has relatively modest effects (i.e., somewhat reduced rectal urgency and increased stiffness during rapid distention) on rectal sensorimotor functions.

Cyclic vomiting syndrome and functional vomiting in adults: association with cannabinoid use in males

BACKGROUND

Cyclic vomiting syndrome (CVS) is characterized by stereotypical episodes of vomiting separated by symptom-free intervals. However, the difficulty encountered in the management of patients with CVS may be a reflection of a deficiency in our understanding of the disorder. We aimed to evaluate whether clinical or gastric emptying (GE) data discriminate patients labeled as having CVS from functional vomiting (FV) or irritable bowel syndrome (IBS).

METHODS

The medical records of patients diagnosed with any vomiting (including CVS, FV) over a 13-year period (1993-2006) at our institution were carefully reviewed. Disease controls were age and gender matched subjects with IBS. Gastric emptying was performed by scintigraphy (99mTc-egg meal). The associations of clinical factors and GE data with patient status (CVS vs FV or IBS) were analyzed.

KEY RESULTS

A total of 82 patients with CVS and 62 FV patients were identified. Younger age [per 10 years, OR = 0.7 (0.5, 0.9)], male gender [OR = 0.4 (0.2, 0.9)], and cannabinoid use [OR = 2.9 (1.2, 7.2)] were significantly associated with CVS compared with FV. However, there were no significant associations between patient status (CVS vs FV) and age, BMI, smoking, alcohol use, gastrointestinal symptoms, or GE. The proportion of cannabinoid users was significantly higher in patients with CVS compared with patients with IBS, whereas proportions for headaches and psychiatric disease were higher in subjects with IBS.

CONCLUSIONS & INFERENCES

Cyclic vomiting syndrome (vs FV) was not associated with clinical factors, but was associated with younger age, male gender and cannabinoid use. A larger proportion of CVS (vs IBS) patients had used cannabinoids.

Clinical predictors of small intestinal bacterial overgrowth by duodenal aspirate culture

BACKGROUND

There has been increasing interest in small intestinal bacterial overgrowth (SIBO) after reports of a link with irritable bowel syndrome (IBS), yet our understanding of this entity is limited.

AIM

Our aim was to estimate the yield of patients undergoing duodenal aspirate culture, and to identify symptoms and features that predict SIBO.

METHODS

A medical chart review of patients who had undergone duodenal aspirate culture at an academic medical centre in 2003 was performed to record clinical characteristics and culture results. The associations between aspirate results and symptoms, medical diagnoses and medication use were assessed using logistic regression.

RESULTS

A total of 675 patients had available aspirate results. Mean age of the sample was 53 (s.d. 17) and 443 (66%) were female patients. Overall, 8% of aspirates were positive for SIBO; 2% of IBS patients had SIBO. Older age, steatorrhoea and narcotic use were associated with SIBO (P < 0.05). PPI use was not associated with SIBO, but was associated with bacterial growth not meeting criteria for SIBO (P < 0.05). Inflammatory bowel disease (IBD), small bowel diverticula and pancreatitis were positively associated with an abnormal duodenal aspirate (P < 0.05), but other conditions including IBS were not associated with SIBO.

CONCLUSION

Older age, steatorrhoea, narcotic use, IBD, small bowel diverticula and pancreatitis were associated with small intestinal bacterial overgrowth based on abnormal duodenal aspirate culture results. However, no clear associations of true small intestinal bacterial overgrowth with IBS or PPI use were detected, in contrast to recent speculation.

Epidemiology, mechanisms, and management of diabetic gastroparesis

Recent evidence of the significant impact of gastroparesis on morbidity and mortality mandates optimized management of this condition. Gastroparesis affects nutritional state, and in diabetics it has deleterious effects on glycemic control and secondary effects on organs that increase mortality. First-line treatments include restoration of nutrition and medications (prokinetic and antiemetic). We review the epidemiology, pathophysiology, impact, natural history, time trends, and treatment of gastroparesis, focusing on diabetic gastroparesis. We discuss pros and cons of current treatment options, including metoclopramide. Second-line therapeutic approaches include surgery, venting gastrostomy or jejunostomy, and gastric electrical stimulation; most of these were developed based on results from open-label trials. New therapeutic strategies for gastroparesis include drugs that target the underlying defects, prokinetic agents such as 5-hydroxytryptamine agonists that do not appear to have cardiac or vascular effects, ghrelin agonists, approaches to pace the stomach, and stem cell therapies.

The effects of methylnaltrexone alone and in combination with acutely administered codeine on gastrointestinal and colonic transit in health

BACKGROUND

The short-term effects of methylnaltrexone (MNTX), a peripherally acting mu-opioid receptor antagonist, on gastrointestinal and colonic transit remain unclear.

AIM

To compare the effects of placebo, codeine, subcutaneous (s.c.) MNTX and codeine with s.c. MNTX on gastrointestinal and colonic transit of solids in healthy humans.

METHODS

In a randomized, parallel-group, double-blind, placebo-controlled trial of 48 healthy volunteers, effects of 6 consecutive days of placebo [s.c. and p.o. (orally), n = 8], codeine (p.o. 30 mg q.d.s., n = 8), MNTX (s.c. 0.30 mg/kg, n = 16) and combined MNTX and codeine (same doses and routes, n = 16) on gastrointestinal and colonic transit were assessed. A validated scintigraphic method was used to measure transit during the last 48 h of treatment. Bowel function was estimated during treatment as well as 1 week preceding treatment using standard diaries. Analysis of covariance was used to assess treatment effects.

RESULTS

Codeine delayed colonic transit [geometric centre at 24 h (P = 0.04) and ascending colon t(1/2) (P = 0.02)] and reduced stool frequency (P = 0.002), but had no effect on stool form. MNTX did not affect transit, stool frequency or stool form, either alone or with codeine (P > 0.3). No drug interaction effects were detected (P > 0.15).

CONCLUSION

Methylnaltrexone does not alter gastrointestinal or colonic transit and does not reverse acute codeine-associated delayed gut transit in health.

The effects of clonidine on symptoms and anorectal sensorimotor function in women with faecal incontinence

BACKGROUND

Women with faecal incontinence and rectal urgency have increased rectal stiffness and sensation.

AIM

To evaluate the effects of clonidine, an alpha(2) -adrenergic agonist, in faecal incontinence.

METHODS

In this open-label uncontrolled study, bowel symptoms and anorectal functions (anal pressures, rectal compliance, and sensation) were assessed before and during treatment with transdermal clonidine (0.2 mg daily, 4 weeks) in 12 women with urge-predominant faecal incontinence.

RESULTS

Clonidine reduced the frequency (17.8 +/- 3.1 before vs. 8.8 +/- 3.9 after, P = 0.03) and number of days with faecal incontinence (11.8 +/- 1.6 before vs. 6.1 +/- 1.8 after, P = 0.02), faecal incontinence symptom severity score (max = 13, 8.3 +/- 0.7 vs. 5.6 +/- 0.9, P < 0.01), and allowed patients to defer defecation for a longer duration (P = 0.03). Although overall effects on anorectal functions were not significant, the treatment-associated reduction in faecal incontinence episodes was associated with increased rectal compliance (r = -0.58, P < 0.05) and reduced rectal sensation. (r = -0.73, P = 0.007 vs. desire to defecate pressure threshold).

CONCLUSIONS

Clonidine improves symptoms in women with faecal incontinence; this improvement is associated with increased rectal compliance and reduced rectal sensitivity. A controlled study is necessary to confirm these observations.

Measurement of abdominal symptoms by validated questionnaire: a 3-month recall timeframe as recommended by Rome III is not superior to a 1-year recall timeframe

BACKGROUND

Rome III incorporates changes in the definition of functional gastrointestinal disorder that involve a 3-month recall time for symptoms, rather than 1-year.

AIM

To validate a new version of the Talley-Bowel Disease Questionnaire (Talley-BDQ) and assess the impact of recall time period on the prevalence of symptoms.

METHODS

A sample of community residents were randomly mailed a survey using 1-year (n = 396) or 3-month recall period (n = 374). We evaluated the reliability and the concurrent validity of the two versions of the questionnaire. The proportions of subjects reporting symptoms in the two versions were compared.

RESULTS

The median (IQR) kappa on symptom-related questions was 0.70 (0.57-0.76) from the 1-year version and 0.66 (0.56-0.77) from the 3-month version. A median kappa of 0.39 (0.19-0.70) and 0.58 (0.39-0.73) was observed for concurrent validation of the 1-year and 3-month versions respectively. Except for gastro-oesophageal reflux symptoms, no differences were observed on the prevalence of clinically relevant symptoms.

CONCLUSION

The revised Talley-BDQ is reliable, with excellent reproducibility and validity. There were few differences in reported symptom rates between the 3-month and 1-year recall time versions of the questionnaire. A 1-year recall time may more efficiently capture infrequent or subtle symptoms.

First-in-human study demonstrating pharmacological activation of heme oxygenase-1 in humans

Heme oxygenase (HO)-1 degrades heme and protects against oxidative stress, but it has not been pharmacologically induced in humans. In this randomized study of 10 healthy volunteers, hemin (3 mg/kg intravenously in 25% albumin) was shown to increase plasma HO-1 protein concentration four- to fivefold and HO-1 activity ~15-fold relative to baseline at 24 and 48 h (placebo -56.41 +/- 6.31 (baseline), 69.79 +/- 13.00 (24 h), 77.44 +/- 10.62 (48 h) vs. hemin -71.70 +/- 9.20 (baseline), 1,126.20 +/- 293.30 (24 h), 1,192.20 +/- 333.30 (48 h)) in four of five subjects as compared with albumin alone (P </= 0.03). This represents the overcoming of a fundamental hurdle to HO-1 research in humans.

Risk factors for chronic diarrhoea in the community in the absence of irritable bowel syndrome

In contrast to irritable bowel syndrome (IBS), the prevalence and risk factors for diarrhoea in the absence of IBS in the community are unknown. We aimed to evaluate potential risk factors for chronic diarrhoea (non-IBS). A valid questionnaire that recorded gastrointestinal symptoms required for a diagnosis of chronic diarrhoea, self-reported measures of potential risk factors, and a somatic symptom checklist was mailed to an age- and gender-stratified random sample of Olmsted County, Minnesota residents (30-64 year). Chronic diarrhoea was defined as reporting one or more of the following symptoms more than 25% of the time in the past 3 months: > or =3 bowel movements a day, loose or watery stools, or faecal urgency. Subjects with IBS (Rome III) were excluded. Of 892 eligible subjects, 653 (73%) responded. Among 523 respondents not reporting IBS, chronic diarrhoea was reported by 148 (28%); 90 (61%) had chronic painless diarrhoea. Chronic diarrhoea was significantly associated with self-reported food sensitivity (OR = 2.05 [1.31-3.20]) and stress (OR = 1.99 [1.03-3.85]). Both remained significant in the adjusted variable models that excluded subjects with any abdominal pain. Female gender (OR = 0.67 [0.45-0.98]) and higher education level (OR = 0.60 [0.39-0.92]) had smaller odds for chronic diarrhoea. No association was detected for age, marital status, body mass index, cigarette or alcohol use, coffee, analgesics, emotional support, pets or water source. Chronic diarrhoea in the absence of IBS is common; self-reported food sensitivity, male gender and a lower level of education are risk factors.

Duodenal mastocytosis, eosinophilia and intraepithelial lymphocytosis as possible disease markers in the irritable bowel syndrome and functional dyspepsia

BACKGROUND

Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common functional disorders without defined pathology. Mast cells and eosinophils interact with T lymphocytes and may alter enteric nerve and smooth muscle function.

AIM

To examine mast cell, eosinophil and intraepithelial lymphocyte populations in duodenal biopsies of subjects with IBS and FD.

METHODS

A random sample of an adult Swedish population (n = 1001; mean age 54 years; 51% female) underwent upper endoscopy and biopsy; 51 cases with FD and 41 cases with IBS were compared with 48 randomly selected controls. Eosinophils were identified by light microscopy; mast cells by immunocytochemistry (CD117). Intraepithelial lymphocytes were counted per 100 enterocytes. Cell counts were quantified by counting the number per high power field (HPF) in 5HPFs in the bulb (D1) and second part of duodenum (D2), summed over 5HPFs at each site.

RESULTS

Cases and controls showed similar demographics. Compared to controls, IELs in IBS-constipation were significantly increased (P = 0.005). Mast cells were significantly increased in IBS in D2 (P < 0.001), while eosinophils were significantly increased in FD in D1 and D2 (P < 0.001).

CONCLUSION

Duodenal mast cell hyperplasia is linked to IBS and eosinophilia to FD, and duodenal biopsy may identify subsets of these disorders.

Pharmacogenetics of low dose clonidine in irritable bowel syndrome

Adrenergic and serotonergic (ADR-SER) mechanisms alter gut (gastrointestinal, GI) sensorimotor functions. We aimed to determine whether candidate ADR-SER genes affect GI responses to low dose clonidine (CLO) in humans. Forty healthy and 120 irritable bowel syndrome (IBS) participants received CLO, 0.1 mg or 0.15 mg b.i.d., for 6 days. At baseline and post-CLO, we measured: gastric volume (GV); satiation volume; rectal compliance, sensation thresholds and ratings with distensions. Genetic variations tested were: alpha2A (C-1291G), alpha2C (Del 322-325), GNbeta3 (C825T) and solute carrier family 6 (neurotransmitter transporter, serotonin), member 4 (SLC6A4) (serotonin transporter linked polymorphic region). CLO reduced volume to satiation (P = 0.002), postprandial GV (P < 0.001), sensation threshold for pain (<0.001); CLO increased rectal compliance (P = 0.024). There were significant associations between post-CLO responses and gene variations for DeltaGV (alpha2A and SLC6A4), rectal sensation of gas (alpha2A, GNbeta3), urgency (alpha2A); and pain (GNbeta3 and SLC6A4); and rectal compliance (SLC6A4). alpha2A, GNbeta3 and SLC6A4 genotypes significantly modify responses to CLO on sensory and motor GI functions in health and IBS.

Associations among binge eating behavior patterns and gastrointestinal symptoms: a population-based study

BACKGROUND

The psychological symptoms associated with binge eating disorder (BED) have been well documented. However, the physical symptoms associated with BED have not been explored. Gastrointestinal (GI) symptoms such as heartburn and diarrhea are more prevalent in obese adults, but the associations remain unexplained. Patients with bulimia have increased gastric capacity. The objective of the study was to examine if the severity of binge eating episodes would be associated with upper and lower GI symptoms.

METHODS

Population-based survey of community residents through a mailed questionnaire measuring GI symptoms, frequency of binge eating episodes and physical activity level. The association of GI symptoms with frequency of binge eating episodes was assessed using logistic regression models adjusting for age, gender, body mass index (BMI) and physical activity level.

RESULTS

In 4096 subjects, BED was present in 6.1%. After adjusting for BMI, age, gender, race, diabetes mellitus, socioeconomic status and physical activity level, BED was independently associated with the following upper GI symptoms: acid regurgitation (P<0.001), heartburn (P<0.001), dysphagia (P<0.001), bloating (P<0.001) and upper abdominal pain (P<0.001). BED was also associated with the following lower GI symptoms: diarrhea (P<0.001), urgency (P<0.001), constipation (P<0.01) and feeling of anal blockage (P=0.001).

CONCLUSION

BED appears to be associated with the experience of both upper and lower GI symptoms in the general population, independent of the level of obesity. The relationship between increased GI symptoms and physiological responses to increased volume and calorie loads, nutritional selections and rapidity of food ingestion in individuals with BED deserves further study.

Effect of a kappa-opioid agonist, i.v. JNJ-38488502, on sensation of colonic distensions in healthy male volunteers

Kappa-opioid receptors are located on visceral pain fibres. JNJ-38488502 is a highly selective tetrapeptide kappa-opioid agonist with little access to the central nervous system and low risk of central nervous system side effects. The aim of the study was to evaluate the effects of i.v. JNJ-38488502 on sensations, including pain, during colonic distension. In a single-centre study, 23 healthy adult males underwent a single-dose, randomized, double-blind crossover study of JNJ-38488502 (0.42 mg kg(-1) i.v. infusion) vs placebo on left colon compliance, sensory thresholds and ratings during standard distensions. One participant could not undergo sensation studies. In the other 22, JNJ-38488502 increased colonic compliance (pressure at half-maximum volume 17.9 +/- 0.8 mmHg) compared to placebo (21.6 +/- 0.9 mmHg, P = 0.007). There was no significant effect on sensory thresholds which, however, were not reached by 44 mmHg in >50% of participants in both treatment phases. There were no significant treatment effects on sensory ratings to distensions at 8, 16, 24, 32 and 36 mmHg above baseline operating pressure. JNJ-38488502 was associated with increased urine output and plasma prolactin, consistent with kappa-opioid receptor activation. This study concluded that i.v. JNJ-38488502 induced kappa-opioid effects, but did not attenuate colonic sensations following random order colonic distension. Further studies of effects on pain sensations in health and disease are required.

Sleep disturbances are linked to both upper and lower gastrointestinal symptoms in the general population

In tertiary referral patients, there is association between altered sleep patterns, functional bowel disorders and altered gut motor function. Body mass index (BMI) is also associated with gastrointestinal (GI) symptoms including diarrhoea, and with sleep disturbances. Our hypothesis is that sleep disturbances are associated with GI symptoms, and this is not explained by BMI. A 48-item-validated questionnaire was mailed to 6939 community participants in Olmsted County, MN. The survey included GI symptoms, sleep disturbance, daily lifestyle and quality of life (QOL). Independent contributions of sleep disturbance to individual symptoms were assessed using logistic regression adjusting for age, gender, lifestyle and mental health status. The association of an overall sleep score with an overall symptom score was examined and the ability of both scores to predict SF-12 physical and mental functioning scores assessed in multiple linear regression models. Among 3228 respondents, 874 (27%) reported trouble staying asleep. There was a significant correlation of overall sleep scores with overall GI symptom scores (partial r = 0.28, P < 0.001). Waking up once nightly at least four times a month was significantly associated with pain, nausea, dysphagia, diarrhoea, loose stools, urgency and a feeling of anal blockage. Trouble falling asleep was significantly associated with rectal urgency. Associations were independent of gender, age, lifestyle factors and BMI. Overall, sleep scores and GI symptom scores were both significant independent predictors of impaired QOL. In the community, reporting poor sleep is associated with upper and lower GI symptoms, but this is independent of BMI.

Sleep disturbances are linked to both upper and lower gastrointestinal symptoms in the general population

In tertiary referral patients, there is association between altered sleep patterns, functional bowel disorders and altered gut motor function. Body mass index (BMI) is also associated with gastrointestinal (GI) symptoms including diarrhoea, and with sleep disturbances. Our hypothesis is that sleep disturbances are associated with GI symptoms, and this is not explained by BMI. A 48-item-validated questionnaire was mailed to 6939 community participants in Olmsted County, MN. The survey included GI symptoms, sleep disturbance, daily lifestyle and quality of life (QOL). Independent contributions of sleep disturbance to individual symptoms were assessed using logistic regression adjusting for age, gender, lifestyle and mental health status. The association of an overall sleep score with an overall symptom score was examined and the ability of both scores to predict SF-12 physical and mental functioning scores assessed in multiple linear regression models. Among 3228 respondents, 874 (27%) reported trouble staying asleep. There was a significant correlation of overall sleep scores with overall GI symptom scores (partial r = 0.28, P < 0.001). Waking up once nightly at least four times a month was significantly associated with pain, nausea, dysphagia, diarrhoea, loose stools, urgency and a feeling of anal blockage. Trouble falling asleep was significantly associated with rectal urgency. Associations were independent of gender, age, lifestyle factors and BMI. Overall, sleep scores and GI symptom scores were both significant independent predictors of impaired QOL. In the community, reporting poor sleep is associated with upper and lower GI symptoms, but this is independent of BMI.

Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects

Alpha-2 adrenergic receptors tonically inhibit colonic motility and the alpha(2)-adrenergic antagonist yohimbine, given intravenously, increased colonic tone in humans. However, the effect of yohimbine on colonic transit in humans is unknown. In this study, 30 healthy volunteers were randomized to yohimbine 16.2 mg p.o. t.i.d. or identical placebo for 7 days. We evaluated gastric emptying, small intestinal, and colonic transit by scinitigraphy, bowel habits, haemodynamics and plasma catecholamines. As cytochrome P450 enzymes metabolize yohimbine, P450 genotypes (CYP2D6 and CYP3A4) were determined in 25 of 30 subjects who consented to genetic studies. The relationship between drug metabolizer status predicted by CYP2D6 and CYP3A4 and effects of yohmibine were assessed. Compared to placebo, yohimbine increased (P < or = 0.02) diastolic blood pressure, plasma noradrenaline concentrations and maximum tolerated volume during the satiation test [yohimbine (1241 +/- 88, mean +/- SEM) vs placebo (1015 +/- 87), P = 0.054]. However, yohimbine did not affect gastrointestinal transit. Based on CYP2D6 and CYP3A4 alleles, seven and 18 subjects were, respectively, extensive (EM) and poor (PM) metabolizers of yohimbine. Compared to EM, PM of yohimbine had a greater increase in plasma noradrenaline (P = 0.1 for PM vs EM), lower maximum tolerated volumes (1120 +/- 95 vs 1484 + 131 mL, P = 0.02), and faster colonic transit (i.e. GC(24) was 3.0 +/- 0.4 vs 2.1 +/- 0.5, P = 0.1). These data suggest that CYP2D6 and CYP3A4 genotypes which determine the metabolism of yohimbine may influence its sympathetic and gastrointestinal effects.

Biliary events and an increased risk of new onset irritable bowel syndrome: a population-based cohort study

BACKGROUND

Prospective data are lacking to determine if irritable bowel syndrome (IBS) is a risk factor for cholecystectomy, or if biliary disease and cholecystectomy predisposes to the development of IBS.

AIM

To test the hypothesis that IBS and biliary tract disease are associated.

METHODS

Validated symptom surveys sent to cohorts of Olmsted County, MN, (1988-1994) with follow-up in 2003. Medical histories were reviewed to determine any 'biliary events' (defined by gallstones or cholecystectomy). Analyses examined were: (i) time to a biliary event post-initial survey and separately and (ii) risk of IBS (Rome II) in those with vs. without a prior biliary event.

RESULTS

A total of 1908 eligible subjects were mailed a follow-up survey. For analysis (i) of the 726 without IBS at initial survey, 44 (6.1%) had biliary events during follow up, in contrast to 5 of 93 (5.4%) with IBS at initial survey (HR 0.8, 95% CI 0.3-2.1). For analysis (ii) of the 59 subjects with a biliary event at initial survey, 10 (17%) reported new IBS on the follow-up survey, while in 682 without a biliary event up to 1.5 years prior to the second survey, 58 (8.5%) reported IBS on follow-up (OR = 2.2, 95% CI 1.1-4.6, P = 0.03).

CONCLUSION

There is an increased risk of new IBS in community subjects who have been diagnosed as having a biliary event.

Asimadoline, a kappa-opioid agonist, and satiation in functional dyspepsia

BACKGROUND

Asimadoline, a kappa-opioid agonist, reduces visceral sensitivity in experimental animal models and may decrease satiation and postprandial fullness in healthy individuals. However, its effect on satiation in functional dyspepsia is unclear, and any symptom benefit has not been explored.

AIM

To evaluate the effects of asimadoline on satiation volume and postchallenge symptoms in functional dyspepsia.

METHODS

A randomized, double-blind trial evaluated gastric satiation and symptoms before and after 8 weeks of asimadoline 0.5 mg (n = 13) or 1.0 mg (n = 13) or placebo (n = 14) b.d. in patients with functional dyspepsia (Rome II). Gastrointestinal Symptom Rating Scale and Nepean Dyspepsia Index were used to assess symptoms during the 8-week treatment.

RESULTS

Over 8 weeks of treatment, asimadoline had no significant effect on maximum-tolerated volume or aggregate symptom score with nutrient drink challenge, and on the mean of the total daily symptom severity score compared to placebo. In a post hoc analysis, asimadoline 0.5 mg significantly increased the maximum-tolerated volume (1217 mL +/- 90.2) compared to placebo (807 mL +/- 111.8) in patients with higher postprandial fullness scores (P = 0.01).

CONCLUSION

Asimadoline overall did not significantly alter maximum-tolerated volume, symptoms postnutrient challenge or symptoms over 8 weeks in functional dyspepsia.

Effect of tolterodine on gastrointestinal transit and bowel habits in healthy subjects

Clinical trials and observations suggest that constipation is an uncommon side effect of treating overactive bladder with the muscarinic receptor antagonist tolterodine. Because muscarinic antagonism inhibits gastrointestinal motor activity, we evaluated the effects of tolterodine on bowel habits, gastrointestinal and colonic transit in healthy subjects. In this double-blind study, 36 healthy subjects were randomized to tolterodine extended release (ER, 4 mg daily) or placebo for 6 days. Gastric emptying (GE), small bowel and colonic transit were assessed on days 4-6 by scintigraphy. Bowel habits were recorded by diaries. Tolterodine did not significantly affect half-time for GE (GE t(half)) [116 +/- 6 min (mean +/- SEM) for placebo vs 126 +/- 7 min for tolterodine], small bowel transit measured by colonic filling at 6 h (45 +/- 6% for placebo vs 36 +/- 6% for tolterodine) or the geometric center of colonic transit at 24 h (2.9 +/- 0.2 for placebo vs 2.6 +/- 0.3 for tolterodine). Subjects who received tolterodine had slightly fewer bowel movements (i.e. 1.34 +/- 0.1 stools per day for placebo vs 1.0 +/- 0.1 for tolterodine; P = 0.02 for treatment effect). Tolterodine did not significantly affect stool consistency or ease of defecation. At the therapeutic dose used to treat overactive bladder, tolterodine did not significantly affect gastrointestinal or colonic transit and had minor effects on bowel habits in healthy subjects. Further studies are necessary to elucidate whether these observations are explained by tolterodine effects at muscarinic receptors which stimulate and inhibit gastrointestinal motility.

Prevalence and risk factors for abdominal bloating and visible distention: a population-based study

BACKGROUND

Abdominal bloating and visible distention are common yet poorly understood symptoms. Epidemiological data distinguishing visible distention from bloating are not available. We aimed to evaluate the prevalence and potential risk factors for abdominal bloating and visible distention separately in a representative US population, and their association with other functional gastrointestinal disorders (FGIDs).

METHODS

The validated Talley Bowel Disease Questionnaire was mailed to a cohort selected at random from the population of Olmsted County, Minnesota. The complete medical records of responders were abstracted; 2259 subjects (53% females; mean age 62 years) provided bloating and distention data.

RESULTS

The age and sex-adjusted (US White 2000) overall prevalence per 100 for bloating was 19.0 [95% confidence interval (CI), 16.9 to 21.2] vs 8.9 (95% CI, 7.2 to 10.6) for visible distention. Significantly increased odds for bloating alone and separately for distention (vs neither) were detected in females, and in those with higher overall Somatic Symptom Checklist (SSC) scores and higher scores of each individual SSC item. Further, females [odds ratio (OR), 1.5; 95% CI, 1.0 to 2.1], higher SSC score (OR, 1.4; 95% CI, 1.1 to 1.8), constipation-predominant irritable bowel syndrome (OR, 2.3; 95% CI, 1.3 to 4.1), dyspepsia (OR, 1.9; 95% CI, 1.1 to 3.2), and gastro-intestinal symptom complex overlap (OR, 1.7; 95% CI, 1.1 to 2.7) significantly increased odds for distention over bloating alone.

CONCLUSIONS

Bloating and distention are common and have similar risk factors; somatisation probably plays a role.

Comparison of breath testing with fructose and high fructose corn syrups in health and IBS

Although incomplete fructose absorption has been implicated to cause gastrointestinal symptoms, foods containing high fructose corn syrup (HFCS) contain glucose. Glucose increases fructose absorption in healthy subjects. Our hypothesis was that fructose intolerance is less prevalent after HFCS consumption compared to fructose alone in healthy subjects and irritable bowel syndrome (IBS). Breath hydrogen levels and gastrointestinal symptoms were assessed after 40 g of fructose (12% solution) prepared either in water or as HFCS, administered in double-blind randomized order on 2 days in 20 healthy subjects and 30 patients with IBS. Gastrointestinal symptoms were recorded on 100-mm Visual Analogue Scales. Breath hydrogen excretion was more frequently abnormal (P < 0.01) after fructose (68%) than HFCS (26%) in controls and patients. Fructose intolerance (i.e. abnormal breath test and symptoms) was more prevalent after fructose than HFCS in healthy subjects (25% vs. 0%, P = 0.002) and patients (40% vs. 7%, P = 0.062). Scores for several symptoms (e.g. bloating r = 0.35) were correlated (P < or = 0.01) to peak breath hydrogen excretion after fructose but not HFCS; in the fructose group, this association did not differ between healthy subjects and patients. Symptoms were not significantly different after fructose compared to HFCS. Fructose intolerance is more prevalent with fructose alone than with HFCS in health and in IBS. The prevalence of fructose intolerance is not significantly different between health and IBS. Current methods for identifying fructose intolerance should be modified to more closely reproduce fructose ingestion in daily life.

An exploratory study of the association of adrenergic and serotonergic genotype and gastrointestinal motor functions

Adrenergic and serotonergic mechanisms alter human gut motor functions. Genotype variation influences phenotype. Our aim was to test the hypothesis that variation in genes that control these functions is associated with gastrointestinal (GI) motor functions in humans with functional GI disorders (FGID). A database of 251 people was assembled by combining genotype data with measurements of gut transit and gastric volumes. Genetic variations evaluated were: alpha(2A) adrenergic (C-1291G), alpha(2C) (Del 332-325), 5-HT transporter (SLC6A4) and GNbeta3 (C825T). We sought associations between motor function or disease groups and genotypes, adjusting for age, gender and body mass index. Among 251 participants, 82 were healthy, 20 with irritable bowel syndrome (IBS) with mixed bowel habit, 49 with constipation-predominant IBS, 67 with diarrhoea-predominant IBS and 33 with functional dyspepsia. For all candidate genes, there was no significant association between motor function and wildtype vs non-wildtype gene status. There were significant interactions between genotype and motility phenotype, specifically GNbeta3 and alpha(2A) and gastric emptying at 4 h. Borderline associations were noted for SCL6A4 and alpha(2A) and postprandial gastric volume, and for alpha(2C) and gastric emptying at 2 h. We conclude that genotype variation may affect gastric motor functions in different FGID phenotypes. However, these candidate genes account for only a limited amount of the variance in gastric function of patients with FGID.

The effect of short-term, low-dose tricyclic and tetracyclic antidepressant treatment on satiation, postnutrient load gastrointestinal symptoms and gastric emptying: a double-blind, randomized, placebo-controlled trial

Antidepressants are commonly prescribed for patients with functional dyspepsia. However, the effect of tricyclic antidepressants on satiation and gastric emptying remains unclear, and there are no data for tetracyclic compounds. To compare the effects of nortriptyline (maximum dose: 50 mg daily) and mirtazapine (30 mg daily) vs placebo on gastric emptying, gastric satiation and postprandial symptoms after a nutrient load in healthy volunteers. Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 14 days of nortriptyline (n = 13), mirtazapine (n = 13), or placebo (n = 14) in healthy volunteers. Validated methods were used to study gastric emptying ((13)C-octanoate) and satiation postnutrient drink test. The three arms were comparable with regard to age, gender, body mass index and hospital anxiety/depression scale. There were no statistically significant effects of mirtazapine or nortriptyline on gastric emptying compared to placebo (P = 0.34). Maximum tolerated volume was similar on drug and placebo (P = 0.56). Aggregate symptom score 30 min postmaximum tolerated volume after nutrient drink challenge on placebo was 132 (+/-21), vs 165 (+/-21) on mirtazapine, and 126 (+/-21) on nortriptyline 50 mg respectively (P = 0.28). Tricyclic and tetracyclic antidepressant agents do not appear to have significant effects on gastric motor or satiation postnutrient challenge in healthy individuals at the doses tested.

A novel partial 5HT3 agonist DDP733 after a standard refluxogenic meal reduces reflux events: a randomized, double-blind, placebo-controlled pharmacodynamic study

BACKGROUND

DDP733, a selective partial 5HT(3) receptor agonist, increases lower oesophageal sphincter pressure in experimental animal models. However, its effect on gastro-oesophageal reflux or lower oesophageal sphincter pressure in humans remains unknown.

AIM

To evaluate the effect of DDP733 on reflux episodes in healthy volunteers receiving a refluxogenic meal.

METHODS

A randomized, double-blind, placebo-controlled cross-over study evaluated the pharmacodynamic effects of DDP733 (0.5, 0.8 and 1.4 mg). Healthy subjects underwent oesophageal manometry and intra-oesophageal multichannel intraluminal impedance and pH after a refluxogenic meal.

RESULTS

DDP733 0.5 mg significantly (P = 0.013) reduced the rate of reflux episodes after a refluxogenic meal from 10 (+/-2.2) on placebo to 6 (+/-1.2) on drug over a 2-h period. DDP733 0.8 and 1.4 mg had no significant effect on reducing the number of reflux episodes. Significant differences in resting lower oesophageal sphincter pressure and the proportion of time pH was <4 (placebo minus drug) after a refluxogenic meal were not observed. No serious adverse events were reported.

CONCLUSION

In healthy subjects, the partial 5HT(3) agonist DDP733 at a dose of 0.5 mg significantly reduces the rate of reflux events, but did not result in a significant change in lower oesophageal sphincter pressure at 1 h postdosing.

Cumulative incidence of chronic constipation: a population-based study 1988-2003

AIM

To estimate the cumulative incidence of chronic constipation and evaluate potential risk factors.

METHODS

In previous cross-sectional studies in 1988, random samples of Olmsted County, MN residents were mailed valid gastrointestinal symptoms surveys. A similar survey was mailed in 2003 to all the remaining eligible subjects who had been mailed to previously. An incident case of chronic constipation was defined as no reported constipation or irritable bowel syndrome on their initial survey but reported constipation on the second survey.

RESULTS

In all, 5507 (79%) subjects responded to the initial survey and 2298 (55%) subjects responded to the second survey in which chronic constipation could be defined. Over 12 years, the cumulative incidence of chronic constipation was 17.4% (14.5, 20.5). Among those less than age 50 years at baseline, the incidence of chronic constipation differed by gender (9.2% in men vs. 18.3% in women). In those over 70 years, the incidence of chronic constipation was more similar for men and women (20.6% vs. 25.0%). The other risk factor associated with new onset chronic constipation was the presence of abdominal pain at baseline [OR = 2.0 (1.3, 3.0)].

CONCLUSION

The cumulative incidence of chronic constipation over more than a decade was almost one in six, and more pronounced in women and the elderly.

Risk factors for chronic constipation and a possible role of analgesics

Constipation has an estimated prevalence of 15% in the general population. However, the etiopathogenesis of this condition remains relatively obscure. This study sought to identify potentially novel risk factors for chronic constipation. A valid self-report questionnaire was mailed to an age- and gender-stratified random sample of Olmsted County, Minnesota residents aged 30-64 years. A logistic regression model that adjusted for age, gender and somatic symptom score (SSC) was used to identify factors associated with chronic constipation. People reporting symptoms of irritable bowel syndrome (IBS) were excluded. Of the 892 eligible subjects, 653 (73%) returned the survey. Among the 523 subjects not reporting IBS symptoms, chronic constipation was reported by 93 (18%) of the respondents. Chronic constipation was significantly associated with use of acetaminophen [>or=7 tablets per week, OR = 2.7 (1.1-6.6)]; aspirin [OR = 1.7 (1.0-2.7)]; non-steroidal anti-inflammatory drugs [OR = 1.8 (1.1-3.0)]; and SSC. No association was detected for age, gender, body mass index, marital status, smoking, alcohol, coffee, education level, food allergy, exposure to pets, stress, emotional support, or water supply. Chronic constipation is associated with use of acetaminophen, aspirin and non-steroidal anti-inflammatory drugs. The explanation of these associations requires further investigation.

Epidemiology of slow and fast colonic transit using a scale of stool form in a community

BACKGROUND

Measurement of gastrointestinal transit is commonly performed in the clinic, but data on transit in the community are lacking.

AIM

To estimate the prevalence of slow and fast colonic transit using stool form, and potential risk factors.

METHODS

A validated self-reported gastrointestinal symptom questionnaire was mailed to 4196 randomly selected members of the community (response rate 54%). One question asked the subject to self-report their stool form using the Bristol Stool Scale.

RESULTS

Overall, 18%, 9% and 73% met stool form criteria for slow, fast or normal colonic transit, respectively. Increased odds for slow transit were observed with a higher Somatic Symptom Checklist score (OR = 1.6; 1.3-2.0), while a decreased odds for slow transit was observed in males relative to females (OR = 0.6; 0.5-0.8). An increased odds for fast transit was observed with higher Somatic Symptom Checklist score (OR = 2.3; 1.7-2.9) and a history of cholecystectomy (OR = 1.8; 1.2-2.8). Increasing body mass index (per 5 units) was associated with decreased odds for slow (OR = 0.85; 0.78-0.93), and an increased odds for fast (OR = 1.1; 1.04-1.24) colonic transit.

CONCLUSION

Based on stool form assessment, nearly one in five community members may have slow colonic transit and one in 12 have accelerated colonic transit.

Does co-administration of a non-selective opiate antagonist enhance acceleration of transit by a 5-HT4 agonist in constipation-predominant irritable bowel syndrome? A randomized controlled trial

Opioid neurons exhibit tonic restraint on intestinal motility; opioid antagonists stimulate peristalsis and increase transit. In vitro, 5-hydroxytryptamine (5-HT4) agonists combined with selective opioid antagonists significantly increased colonic propulsion relative to a 5-HT4 agonist alone. We hypothesized that the combination of 5-HT4 agonist and non-selective opioid antagonist enhances intestinal transit more than either treatment alone in female constipation-predominant irritable bowel syndrome (C-IBS) patients. Our aim was to examine the effect of tegaserod 6 mg b.i.d. alone and combined with naltrexone 50 mg on intestinal transit and stool characteristics in females with C-IBS. Forty-eight patients were randomized to tegaserod alone, naltrexone alone or in combination with tegaserod or placebo for 6 days. Small bowel, ascending colon half-life (in pharmacokinetics) (t1/2), and colonic geometric centre (8, 24, 48 h) were assessed by scintigraphy. Tegaserod increased small bowel (P < 0.01) and colon transit (P < 0.01). Naltrexone did not accelerate colonic transit relative to placebo. Combination treatment did not significantly accelerate transit relative to tegaserod alone. Tegaserod and tegaserod with naltrexone resulted in looser stool form (P < 0.01). In female C-IBS patients, tegaserod accelerates small bowel and colon transit and contributed to looser stool consistency. Use of naltrexone, 50 mg, does not support the hypothesis that combination of 5-HT4 agonist and non-selective opioid antagonist enhances intestinal transit.

Effects of glucagon-like peptide-1 and sympathetic stimulation on gastric accommodation in humans

In humans, glucagon-like peptide-1 (GLP-1) delays gastric emptying by inhibiting vagal activity and also increases gastric volumes, by unclear mechanisms. Because GLP-1 inhibits intestinal motility by stimulating the sympathetic nervous system in rats, we assessed the effects of a GLP-1 agonist and yohimbine, an alpha(2)-adrenergic antagonist, on gastric volumes in humans. In this double-blind study, 32 healthy volunteers were randomized to placebo, a GLP-1 agonist, yohimbine or GLP-1 and yohimbine. Gastric volumes (fasting predrug and postdrug, and postprandial postdrug) were measured by (99m)Tc single photon emission computed tomography imaging. Plasma catecholamines and haemodynamic parameters were assessed. Compared with placebo, GLP-1 increased (P = 0.03) but yohimbine did not affect fasting gastric volume. However, GLP-1 plus yohimbine increased (P < 0.001) postprandial gastric accommodation vs placebo and vs GLP-1 alone [postprandial volume change = 542 +/- 29 mL (mean +/- SEM, placebo), 605 +/- 31 mL (GLP-1), 652 +/- 54 mL (yohimbine) and 810 +/- 37 mL (GLP-1 and yohimbine)]. Plasma noradrenaline and dihydroxyphenylglycol concentrations were higher for yohimbine vs placebo and for GLP-1 and yohimbine vs GLP-1. Yohimbine stimulates central sympathetic activity and in combination with GLP-1, augments postprandial accommodation in humans.

Effect of the NK(3) receptor antagonist, talnetant, on rectal sensory function and compliance in healthy humans

Visceral hypersensitivity is important in the pathophysiology of irritable bowel syndrome and thus a target for modulation in drug development. Neurokinin (NK) receptors, including NK(3) receptors, are expressed in the motor and sensory systems of the digestive tract. The aim of this study was to compare the effects of two different doses (25 and 100 mg) of the NK(3) receptor antagonist, talnetant (SB223412) with placebo on rectal sensory function and compliance in healthy volunteers studied at two centres. Rectal barostat tests were performed on 102 healthy volunteers, randomized to receive either oral talnetant 25 or 100 mg or placebo over 14-17 days. Studies were performed on three occasions: day 1 immediately prior to 1st dose, day 1 4 h postdose, and after 14- to17-day therapy. Compliance, and pressure thresholds for first sensation, urgency, discomfort and pain were measured using ascending method of limits, and sensory intensity ratings for gas, urgency, discomfort and pain determined during four random phasic distensions (12, 24, 36 and 48 mmHg). Talnetant had no effect on rectal compliance, sensory thresholds or intensity ratings compared with placebo. In general, the results obtained at the two centres differed minimally, with intensity scores at one centre consistently somewhat lower. At the doses tested, talnetant has no effect on rectal compliance or distension-induced rectal sensation in healthy participants.

Overlap of gastro-oesophageal reflux disease and irritable bowel syndrome: prevalence and risk factors in the general population

BACKGROUND

Gastro-oesophageal reflux disease (GERD) and irritable bowel syndrome may occur more often than expected by chance, but little community data exists and risk factors are unknown.

AIM

To determine prevalence and risk factors for overlap of GERD and irritable bowel disease.

METHODS

Population-based, cross-sectional survey was conducted by mailing a valid symptom questionnaire to eligible residents of Olmsted County, MN, aged 30-95 years. Irritable bowel syndrome were defined by Rome III; GERD was defined by weekly or more frequent heartburn and/or acid regurgitation.

RESULTS

2298 questionnaires returned (women 52%, 55% response). Irritable bowel syndrome and GERD occurred together more commonly than expected by chance; the prevalence of irritable bowel syndrome-GERD overlap, GERD alone and irritable bowel syndrome alone were 3%, 15% and 5% in men, and 4%, 14% and 10% in women, respectively. Predictors of irritable bowel syndrome-GERD overlap vs. irritable bowel syndrome alone, and separately, GERD alone, were insomnia (OR 1.3, 95% CI: 1.06-1.70; OR 1.5, 95% CI: 1.13-1.90, respectively) and frequent abdominal pain (OR 3.9, 2.2-6.7; OR 1.8, 1.02-3.2, respectively). An additional predictor of irritable bowel syndrome-GERD overlap vs. GERD alone was higher somatization (OR 1.7, 1.1-2.4) and for irritable bowel syndrome-GERD overlap vs. irritable bowel syndrome alone was a higher body mass index (OR 1.0, 1.003-1.07).

CONCLUSIONS

Irritable bowel syndrome and GERD overlap is common in the population and does not occur by chance.

Age at onset of inflammatory bowel disease and the risk of surgery for non-neoplastic bowel disease

BACKGROUND

There is conflicting data regarding the response to medical and surgical therapy for inflammatory bowel disease with respect to age at disease onset.

AIM

To determine if the age at onset of Crohn's disease and ulcerative colitis is a risk factor for surgery for non-neoplastic bowel disease.

METHODS

This was a case-control study of patients evaluated between 1998 and 2001. Cases had undergone an initial operation for bowel disease. Controls were matched 1:1 for gender, disease subtype, date of first visit (+/-2 years), time from diagnosis prior to first visit (+/-3 years) and duration of follow-up. Association with age, disease extent, smoking history, medication use and co-morbidities vs. case/control status was assessed using multiple variable conditional logistic regression to estimate the odds ratio (OR) and 95% confidence intervals (CI) for undergoing surgery.

RESULTS

Among 132 Crohn's patients, older patients had lower odds for surgery (OR per 5 years, 0.86; 95% CI: 0.75-0.98). The rate of surgery for non-neoplastic bowel disease was not significantly associated with disease distribution, co-morbidities or cigarette smoking. Among 234 ulcerative colitis patients, the rate of surgery was unrelated to age, disease extent, co-morbidities or cigarette smoking,

CONCLUSIONS

For Crohn's disease, but not ulcerative colitis, the risk of surgery for non-neoplastic bowel disease decreases with increasing age at diagnosis, irrespective of disease distribution and history of cigarette smoking.

A double-blind, randomized, placebo-controlled trial of itopride (100 and 200 mg three times daily) on gastric motor and sensory function in healthy volunteers

Itopride, a dopamine D2 antagonist and acetylcholinesterase inhibitor, significantly improved symptoms in patients with functional dyspepsia in one phase II randomized trial. However, the mechanisms by which itopride may improve symptoms are unknown. We aimed to compare the effects of two doses of itopride and placebo on gastric volumes, gastric emptying, small bowel transit and satiation in female and male healthy volunteers. Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 7 days of itopride 100 mg (n = 16) or 200 mg (n = 15) or placebo (n = 15) t.i.d. Validated methods were used to study gastric accommodation (single photon emission computed tomography), gastric emptying and orocecal transit and satiation postnutrient challenge. The three arms were comparable with regard to age, gender and body mass index. There were no statistically significant effects of itopride on gastric emptying, orocecal transit, fasting gastric volume, maximum tolerated volume or aggregate symptom score with nutrient drink challenge. Postprandial (PP) change in gastric volume differed in the three groups (P = 0.019): 625[+/-28 (SEM)], 555(+/-26) and 512(+/-33) in placebo, itopride 100 and 200 mg groups, respectively. In healthy subjects, itopride reduced total PP gastric volume without accelerating gastric emptying or significantly altering gastric motor and sensory function in healthy individuals.

The changing incidence of oesophageal and gastric adenocarcinoma by anatomic sub-site

BACKGROUND

The incidence rates of gastric and oesophageal adenocarcinoma are changing significantly, but little is known about specific sub-sites.

AIM

To use a population-based approach to describe the trends in the site-specific incidence of oesophageal and gastric adenocarcinoma.

METHODS

Using the Rochester Epidemiology Project, all cases of gastric and oesophageal adenocarcinoma among Olmsted County, Minnesota, residents first diagnosed between 1971 and 2000 were identified (n = 186). Complete in-patient and out-patient records were reviewed and site determined from pathological, surgical, endoscopic and radiological reports.

RESULTS

Between the decades of 1971-1980 and 1991-2000, the incidence of oesophageal adenocarcinoma increased significantly from 0.4 to 2.5 per 100 000 person-years. The incidence of adenocarcinoma of the oesophagogastric junction also increased from a rate of 0.6 to 2.2 per 100 000 person-years. The incidence rate of cancer involving the gastric cardia was stable but the incidence of adenocarcinoma involving distal gastric sites declined. Combined oesophageal and oesophagogastric junction adenocarcinoma (4.7 per 1 000 000 person-years) was as common as gastric adenocarcinoma (3.4 per 100 000 person-years) in 1991-2000.

CONCLUSIONS

The incidence rates of adenocarcinoma involving proximal gastric sub-sites do not appear to be increasing in a manner similar to those involving oesophageal sub-sites.

Pharmacodynamic effects of a novel prokinetic 5-HT receptor agonist, ATI-7505, in humans

ATI-7505, an investigational 5-HT(4) receptor agonist, was designed to have similar activity as cisapride without the cardiac adverse effects, i.e. without QT prolongation. In addition, ATI-7505 is not metabolized by CYP450. The aim of the study was to assess the effect of ATI-7505 on gastrointestinal (GI) and colonic transit in healthy humans. A randomized, parallel-group, double-blind, placebo-controlled study evaluated effects of 9-day treatment with ATI-7505 (3, 10 or 20 mg t.i.d.) on scintigraphic GI and colonic transit in healthy volunteers (12 per group). Primary endpoints were gastric-emptying (GE) T(1/2), colonic geometric centre (GC) at 24 h and ascending colon (AC) emptying T(1/2). Daily stool diaries were kept. Analysis of covariance assessed overall treatment group differences, followed by post hoc unadjusted pairwise comparisons. There were borderline overall treatment effects (decrease) on GE T(1/2) (P = 0.154); the 20 mg t.i.d. of ATI-7505-accelerated GE vs placebo (P = 0.038). ATI-7505 increased colonic transit (GC24, P = 0.031) with fastest transit at 10 mg t.i.d. vs placebo (P = 0.065). ATI-7505 accelerated AC emptying T(1/2) (overall P = 0.075) with 10 mg dose vs placebo (P = 0.042). There was looser stool (Bristol stool form scale, overall P = 0.056) with the 10 and 20 mg t.i.d. doses. No safety issues were identified. ATI-7505 accelerates overall colonic transit and tends to accelerate GE and AC emptying and loosen stool consistency.