Integrated fecal microbiome-metabolome signatures reflect stress and serotonin metabolism in irritable bowel syndrome

To gain insight into the complex microbiome-gut-brain axis in irritable bowel syndrome (IBS), several modalities of biological and clinical data must be combined. We aimed to identify profiles of fecal microbiota and metabolites associated with IBS and to delineate specific phenotypes of IBS that represent potential pathophysiological mechanisms. Fecal metabolites were measured using proton nuclear magnetic resonance (¹H-NMR) spectroscopy and gut microbiome using shotgun metagenomic sequencing (MGS) in a combined dataset of 142 IBS patients and 120 healthy controls (HCs) with extensive clinical, biological and phenotype information. Data were analyzed using support vector classification and regression and kernel t-SNE. Microbiome and metabolome profiles could distinguish IBS and HC with an area-under-the-receiver-operator-curve of 77.3% and 79.5%, respectively, but this could be improved by combining microbiota and metabolites to 83.6%. No significant differences in predictive ability of the microbiome-metabolome data were observed between the three classical, stool pattern-based, IBS subtypes. However, unsupervised clustering showed distinct subsets of IBS patients based on fecal microbiome-metabolome data. These clusters could be related plasma levels of serotonin and its metabolite 5-hydroxyindoleacetate, effects of psychological stress on gastrointestinal (GI) symptoms, onset of IBS after stressful events, medical history of previous abdominal surgery, dietary caloric intake and IBS symptom duration. Furthermore, pathways in metabolic reaction networks were integrated with microbiota data, that reflect the host-microbiome interactions in IBS. The identified microbiome-metabolome signatures for IBS, associated with altered serotonin metabolism and unfavorable stress response related to GI symptoms, support the microbiota-gut-brain link in the pathogenesis of IBS.

Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

AIM: To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience.

METHODS: We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters: color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the paired-samples t test.

RESULTS: Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0% vs 82.9%, P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%.

CONCLUSION: After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.

Alterations in mucosal neuropeptides in patients with irritable bowel syndrome and ulcerative colitis in remission: a role in pain symptom generation?

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by chronic abdominal pain. The transient receptor potential vanilloid 1 (TRPV1) channel, which is involved in visceral pain signalling, has been shown to be up-regulated in IBS. Activation of TRPV1 leads to the release of neuropeptides, such as somatostatin and substance P (SP). We hypothesized that increased pain perception in IBS could be explained by increased transcription in TRPV1 and/or altered levels of neuropeptides. We therefore assessed the transcription of TRPV1 and the mucosal concentration of somatostatin and SP in IBS in comparison to healthy volunteers and patients with ulcerative colitis (UC) in remission as disease controls, and to ascertain their relationship to pain symptoms.

METHOD

Sigmoid colonic mucosal samples were collected from 12 patients with IBS, 34 patients with UC in remission and 9 healthy volunteers, in which groups TRPV1 mRNA levels were determined using quantitative polymerase chain reaction and neuropeptide concentrations by radioimmunoassay. Pain symptom intensity was determined by questionnaires.

RESULTS

Transcription of TRPV1 as well as the concentration of neuropeptides were significantly higher in IBS, but only the former correlated with pain symptom severity.

CONCLUSION

Increased transcription of TRPV1 may provide a possible explanation for pain generation in IBS. While the neuropeptides SP and somatostatin were both found to be increased in IBS, these changes are not sufficient to explain pain generation. Pain generation in IBS is probably explained by a complex redundancy in the regulation of local nociceptive mechanisms, which remains a subject of intensive investigation.

Irritable bowel syndrome: methods, mechanisms, and pathophysiology. Methods to assess visceral hypersensitivity in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, characterized by recurrent abdominal pain or discomfort in combination with disturbed bowel habits in the absence of identifiable organic cause. Visceral hypersensitivity has emerged as a key hypothesis in explaining the painful symptoms in IBS and has been proposed as a "biological hallmark" for the condition. Current techniques of assessing visceral perception include the computerized barostat using rectal distensions, registering responses induced by sensory stimuli including the flexor reflex and cerebral evoked potentials, as well as brain imaging modalities such as functional magnetic resonance imaging and positron emission tomography. These methods have provided further insight into alterations in pain processing in IBS, although the most optimal method and condition remain to be established. In an attempt to give an overview of these methods, a literature search in the electronic databases PubMed and MEDLINE was executed using the search terms "assessment of visceral pain/visceral nociception/visceral hypersensitivity" and "irritable bowel syndrome." Both original articles and review articles were considered for data extraction. This review aims to discuss currently used modalities in assessing visceral perception, along with advantages and limitations, and aims also to define future directions for methodological aspects in visceral pain research. Although novel paradigms such as brain imaging and neurophysiological recordings have been introduced in the study of visceral pain, confirmative studies are warranted to establish their robustness and clinical relevance. Therefore, subjective verbal reporting following rectal distension currently remains the best-validated technique in assessing visceral perception in IBS.

Irritable bowel syndrome: methods, mechanisms, and pathophysiology. Methods to assess visceral hypersensitivity in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, characterized by recurrent abdominal pain or discomfort in combination with disturbed bowel habits in the absence of identifiable organic cause. Visceral hypersensitivity has emerged as a key hypothesis in explaining the painful symptoms in IBS and has been proposed as a "biological hallmark" for the condition. Current techniques of assessing visceral perception include the computerized barostat using rectal distensions, registering responses induced by sensory stimuli including the flexor reflex and cerebral evoked potentials, as well as brain imaging modalities such as functional magnetic resonance imaging and positron emission tomography. These methods have provided further insight into alterations in pain processing in IBS, although the most optimal method and condition remain to be established. In an attempt to give an overview of these methods, a literature search in the electronic databases PubMed and MEDLINE was executed using the search terms "assessment of visceral pain/visceral nociception/visceral hypersensitivity" and "irritable bowel syndrome." Both original articles and review articles were considered for data extraction. This review aims to discuss currently used modalities in assessing visceral perception, along with advantages and limitations, and aims also to define future directions for methodological aspects in visceral pain research. Although novel paradigms such as brain imaging and neurophysiological recordings have been introduced in the study of visceral pain, confirmative studies are warranted to establish their robustness and clinical relevance. Therefore, subjective verbal reporting following rectal distension currently remains the best-validated technique in assessing visceral perception in IBS.

Opportunistic screening of hospital staff using primary colonoscopy: participation, discomfort and willingness to repeat the procedure

BACKGROUND

Participation in and tolerability of primary colonoscopy screening are presumed to be relatively low. The present study aimed to test its feasibility in a well-informed population of hospital staff using an intensive information campaign, and to identify factors associated with screening colonoscopy rated as uncomfortable.

METHODS

Data were collected using standardized forms.

RESULTS

Out of 1,090 invited employees (50-65 years), 447 (41.0%) participated. Bowel preparation and colonoscopy were rated as 'somewhat to very uncomfortable' by 79.5 and 21.9%, respectively. 96.3% of participants were willing to repeat colonoscopy in the future. Participants rating colonoscopy as uncomfortable were more likely unwilling to repeat the procedure (OR 8.026, CI 2.667-24.154). Multivariate analysis (age- and gender-adjusted) showed an association of colonoscopy rated as uncomfortable with: abdominal pain during colonoscopy (OR 3.185, CI 1.642-6.178), other pain (OR 2.428, CI 1.335-4.416), flatulence (OR 2.175, CI 1.219-3.881), embarrassment (OR 2.843, CI 1.350-5.989), abdominal pain after colonoscopy (OR 1.976, CI 1.041-3.751), and a prolonged procedure time (OR 1.000, CI 1.000-1.001).

CONCLUSIONS

Acceptance of primary colonoscopy screening for colorectal neoplasia was high, although participants with symptoms during and after colonoscopy were more likely to rate colonoscopy as uncomfortable. This type of opportunistic screening procedure is suitable for the introduction of screening programs and may be useful in areas that have no access to population-based screening.

Does meal ingestion enhance sensitivity of visceroperception assessment in irritable bowel syndrome?

BACKGROUND

Visceral hypersensitivity is frequently observed in irritable bowel syndrome (IBS). Previous studies have shown that administration of a meal can aggravate symptoms or increase visceroperception in IBS patients. We investigated whether meal ingestion could increase the sensitivity of the barostat procedure for the detection of visceral hypersensitivity in IBS patients.

METHODS

Seventy-one IBS patients and 30 healthy controls (HC) were included in the study. All subjects underwent a barostat procedure under fasted and postprandial conditions to measure visceroperception. Urge, discomfort, and pain were scored on a visual analog scale. Furthermore, percentages of hypersensitive IBS patients and HC were calculated and dynamic rectal compliance was assessed.

KEY RESULTS

In IBS patients, urge, discomfort, and pain scores were significantly increased postprandially vs the fasted state. The HC showed increased scores for urge and pain only. Rectal dynamic compliance remained unaltered in both groups. Postprandial hypersensitivity percentages did not significantly differ vs the fasted state in IBS patients, nor in HC.

CONCLUSIONS & INFERENCES

Postprandial barostat measurement enhances visceroperception in IBS but has no added value to detect visceral hypersensitivity in individual IBS patients.

Cardiopulmonary events during primary colonoscopy screening in an average risk population

BACKGROUND

Large colorectal cancer screening studies using primary colonoscopy have reported a low risk of major complications. Studies on diagnostic and therapeutic colonoscopy have pointed to a frequent occurrence of(minor) cardiopulmonary events, and with the steady increase of colonoscopy screening, it is important to investigate their occurrence in colonoscopy screening.

METHODS

This study describes the frequency of bradycardia(pulse rate <60 min-1), hypotension (systolic blood pressure(SB P) <90 mmHg), hypoxaemia (blood oxygenation, SaO2<90%) and ECG changes during colonoscopy screening in an average-risk population (hospital personnel, n=214,mean age 54.0±3.8, 39.3% male), without significant comorbidity) and aims at identifying subject-related and/or endoscopic factors associated with their occurrence. All data were collected prospectively. During 214 consecutive primary screening colonoscopies under conscious sedation(midazolam and pethidine), on top of pulse rate and SaO2,blood pressure and a three-channel ECG were recorded every five minutes.

RESULTS

No major complications or relevant ECG changes occurred. Hypoxaemia occurred in 119 (55.6%),hypotension in 19 (8.9%) and bradycardia in 12 subjects(5.6%). In multivariate analysis, the sedation level 3 increased the risk of hypoxaemia (OR 4.8, CI 1.7-13.7), and incomplete colonoscopy (OR 5.3, CI 1.6-18.1) was associated with hypotension. Subjects with bradycardia had a longer mean procedure time (38±12 vs. 29±12 min, p<0.05), which did not turn out as a risk factor in a multivariate analysis.

CONCLUSIONS

Mainly procedure-related and not subject-related factors were found to be associated with the occurrence of cardiopulmonary events in primary colonoscopy screening in this relatively healthy screening population.

Effect of triglycerides with different fatty acid chain length on superior mesenteric artery blood flow

Fat stimulates superior mesenteric artery (SMA) blood flow. Little is known, however, about the influence of fatty acid chain length on SMA flow. The present study was performed to compare the effect of long chain triglycerides (LCT, corn oil), very long chain triglycerides (VLCT, fish oil) and medium chain triglycerides (MCT) on SMA flow. A total of seven healthy volunteers (four men, three women; aged 26 +/- 4 years) participated in three experiments, performed in random order during 60 min continuous intra-duodenal infusion of either LCT (30 mL h(-1); 240 kcal h-1), equicaloric VLCT (30 mL h(-1); 240 kcal h(-1)) or MCT in equimolar (15 mL h(-1); 113 kcal h(-1)) and equicaloric amount (30 mL h(-1); 225 kcal h(-1)). Basal and stimulated SMA blood flow were measured by Doppler ultrasonography. At regular intervals blood samples were taken for measurement of plasma cholecystokinin (CCK) and plasma peptide YY (PYY). Basal SMA blood flow volumes were not significantly different among the LCT, VLCT and MCT experiments (426 +/- 135, 460 +/- 114 and 503 +/- 177 mL min(-1), respectively). The SMA flow increased significantly (P < 0.05) during fat infusion but was significantly higher during LCT (1460 +/- 692 mL min-1) compared with VLCT (1061 +/- 384 mL min-1), MCT 15 mL h(-1) (870 +/- 286 mL min(-1)) and MCT 30 mL h-1 (904 +/- 223 mL min(-1)). Plasma CCK levels increased significantly (P < 0.05) during LCT and VLCT but not during MCT infusion. No correlation was found between SMA flow and plasma CCK levels (r = 0.27; P = 0.2) The SMA blood flow in response to triglycerides is dependent on fatty acid chain length. This chain length-dependent blood flow response is, however, not linear and is not related to plasma CCK levels.

Faecal elastase-I: helpful in analysing steatorrhoea?

BACKGROUND

The faecal elastase-1 test (FE-1) is considered easy to perform and sensitive to detect severe and moderate exocrine pancreatic insufficiency. However, little information is available on the specificity of this test in the analysis of steatorrhoea. Our aim was to evaluate the clinical value of FE-1 in the analysis of patients sent in for faecal fat determination.

METHODS

Stool samples were collected over 24 hours in 40 healthy controls and 119 patients: 58 patients with chronic pancreatitis and 61 nonpancreatic disease patients with chronic diarrhoea. Faecal fat excretion was determined and FE-1 was measured using a commercially available ELISA kit, which employs two monoclonal antibodies to bind to two distinct epitopes of human pancreatic elastase-1.

RESULTS

Faecal elastase-1 test shows good reproducibility. The test lacks sensitivity in detecting exocrine pancreatic insufficiency and chronic pancreatitis (68 and 59%, respectively). However, it is specific with respect to differentiating pancreatic from nonpancreatic causes in patients with steatorrhoea.

CONCLUSION

FE-1 lacks sensitivity to detect chronic pancreatitis. It can serve as a simple, noninvasive method to determine the aetiology of steatorrhoea.

Pancreatic polypeptide secretion in patients with chronic pancreatitis and after pancreatic surgery

AIM

We investigated polypeptide (PP) secretion under basal conditions, in response to bombesin infusion and to meal ingestion in patients with chronic pancreatitis (CP) and patients after different types of pancreatic surgery.

METHODS

Included were patients with CP without (n = 20) and with (n = 30) exocrine pancreatic insufficiency, patients after duodenum preserving resection of the head of the pancreas (DPRHP; n = 20), after Whipple's procedure (n = 19), following distal pancreatectomy (DP; n = 12), and healthy controls (n = 36).

RESULTS

In CP patients basal and bombesin stimulated PP levels were significantly (p<0.01) reduced compared to controls only when exocrine insufficiency was present. Meal-stimulated PP secretion was significantly (p<0.01-0.05) reduced in CP patients both with and without exocrine insufficiency. Plasma PP peak increments after bombesin and meal ingestion correlated significantly with exocrine function. Basal PP, meal, and bombesin-stimulated PP secretion had low sensitivities of 22%, 42%, and 60% respectively, in detecting chronic pancreatitis. In patients after pancreatic surgery that included pancreatic head resection (DPRHP or Whipple operation) basal and stimulated PP secretion were significantly (p<0.01-0.05) reduced.

CONCLUSION

Basal and meal or bombesin-stimulated PP levels are significantly reduced in patients with CP only when exocrine insufficiency is present. Determination of plasma PP levels has low sensitivity and is not useful in detecting chronic pancreatitis without exocrine insufficiency. In patients after pancreatic surgery, PP secretion is dependent on the type of operation (head vs tail resection).

Proximal gastric motor and sensory function in slow transit constipation

BACKGROUND

Slow transit constipation may be part of a more generalized gastrointestinal motility disorder.

METHODS

Gastric motor and sensory function were evaluated using a barostat in 17 patients with slow transit constipation and in 16 healthy controls. A step-wise isobaric distension procedure was performed, followed by a barostat procedure including a liquid meal. Symptoms were scored using visual analog scales. Plasma levels of gastrointestinal hormones were determined postprandially.

RESULTS

Proximal gastric compliance was significantly reduced in the patients. Basal gastric volume did not differ between patients and controls. Postprandial fundus relaxation was significantly reduced in the patients and correlated significantly with daily upper gastrointestinal symptoms. Postprandial secretion of cholecystokinin and gastrin was reduced in the patients.

CONCLUSIONS

In patients with slow transit constipation, proximal gastric compliance is reduced and postprandial fundus relaxation is impaired. These findings support the hypothesis that slow transit constipation may be part of a pan-enteric disorder.

Prospective study of the effect of laparoscopic Nissen fundoplication on reflux mechanisms

BACKGROUND

Laparoscopic Nissen fundoplication effectively reduces acid reflux and reflux symptoms. Little is known about the effect on reflux mechanisms, especially on transient lower oesophageal sphincter relaxations (TLOSRs).

METHODS

Twenty-seven patients were studied prospectively before and after laparoscopic Nissen fundoplication, by simultaneous recording of pH and lower oesophageal sphincter (LOS) characteristics using sleeve manometry. In all of the 27 patients the operation was judged successful, based on major improvement or resolution of reflux symptoms and acid reflux. Vagus nerve integrity was studied indirectly by the secretion of pancreatic polypeptide (PP) in response to insulin-induced hypoglycaemia.

RESULTS

After fundoplication basal LOS pressure increased significantly from mean(s.e.m.) 13(1) to 22(1) mmHg (P < 0.001). Laparoscopic Nissen fundoplication significantly decreased the frequency of TLOSR in the fasting period from mean(s.e.m.) 2.5(0.5) to 0.6(0.2) per h, and in the postprandial period from 4.0(0.4) to 1.3(0.3) per h (P < 0.01). The percentage of TLOSRs associated with reflux also decreased significantly from 24(10) to 0(0) per cent in the fasting period and from 42(6) to 12(6) per cent in the postprandial period, before and after fundoplication respectively (P < 0.01). After operation the PP response was abnormal in three patients, pointing to vagus nerve dysfunction. Postoperative TLOSR frequency and LOS pressure were no different between patients with and without vagus nerve dysfunction.

CONCLUSION

Laparoscopic Nissen fundoplication significantly increased fasting and postprandial LOS pressure and significantly decreased the rate of TLOSR. This resulted in a significant reduction in oesophageal acid exposure but postprandial LOS characteristics were preserved.

Ileoanal pouch function is related to postprandial pouch tone

BACKGROUND

Functional impairments are frequently observed in patients with an ileoanal pouch. Meal ingestion increases pouch tone and motility. Little is known, however, about the influence of meal-stimulated pouch characteristics on pouch function. The aim was to characterize basal and postprandial pouch motor and sensory characteristics in relation to clinical pouch function in patients with an ileoanal pouch.

METHODS

Nineteen patients with an ileoanal pouch, without faecal incontinence but with either a high stool frequency (n = 8) or an adequate stool frequency (n = 11), underwent pressure distension of the pouch, by which pouch compliance and sensitivity characteristics were assessed using an electronic barostat. A set pressure procedure was performed to assess the influence of a meal on pouch tone and motility.

RESULTS

Mean(s.d.) compliance was 10(6) and 11(4) ml/mmHg in the groups with poor and adequate pouch function respectively (P not significant). Mean(s.d.) visual analogue scale scores (0-10 cm) for urge at the highest pressure of 28 mmHg were 2.3(1.0) versus 2.3(2.4) cm respectively (P not significant); those for pain were 0.8(1.0) versus 0.5(0.7) (P not significant). Postprandially mean(s.d.) pouch volume decreased by 70(24) per cent in the group with poor pouch function and 29(25) per cent in the group with adequate pouch function (P < 0.01). The frequency and amplitude of phasic pouch contractions increased significantly postprandially, but no differences in motility characteristics were observed between the two groups.

CONCLUSION

In patients with uniform pouch design and follow-up after pouch construction, pouch compliance and sensitivity were no different between patients with normal and high stool frequency; however, postprandial pouch tone was increased significantly in patients with a high stool frequency.

Does Helicobacter pylori gastritis affect motor function of proximal stomach in dyspeptic patients?

The role of Helicobacter pylori infection in proximal gastric motor function and its relation to symptoms in patients with functional dyspepsia is still unclear. We prospectively studied 26 patients with dyspepsia, no structural abnormalities found during endoscopy and biopsy-proven Helicobacter pylori-positive gastritis before and three months after Helicobacter pylori treatment. We used an 11-item score list to evaluate symptoms, gastric biopsies for histology, and a gastric barostat (isobaric inflation-deflation) for proximal gastric motility. Minimal distending pressure (MDP), mean gastric volume at operating pressure, AUC of inflation-deflation cycles, and hysteresis (difference in AUC during inflation and AUC during deflation) were calculated. After three months, Helicobacter pylori was eradicated in 96% of patients. MDP, mean gastric volume at operating pressure, gastric compliance, and hysteresis did not change significantly. Aggregate symptom score as well as histology scores in antrum and corpus decreased significantly. Reduction in postprandial pain correlated with a change in hysteresis (r = 0.567, P < 0.01), but other symptoms did not. Reduction of corpus inflammatory activity correlated with changes in hysteresis (r = 0.604, p < 0.005), suggesting that the stomach attains it original shape faster when inflammation is reduced. These observations suggest that inflammatory changes or release of inflammatory substances associated with Helicobacter pylori infection may influence proximal gastric motor characteristics.

Provocation of transient lower esophageal sphincter relaxations by gastric distension with air

OBJECTIVES

Transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism permitting not only gastroesophageal reflux but also venting of air from the stomach. Triggering of TLESRs is provoked by gastric distension. Antireflux surgery is associated with impaired ability to belch. It is not known whether a reduced capacity to belch results from postoperative reduction in TLESRs.

METHODS

We studied the occurrence of TLESRs, common cavities (indicator for gas gastroesophageal reflux), and belching after standardized acute gastric distension by air insufflation (750 ml). Control subjects (n = 10), patients with gastroesophageal reflux disease (GERD) (n = 22), and patients after fundoplication (n = 24) were studied. LES and esophageal motilities were recorded with perfusion manometry.

RESULTS

Gastric distension with air significantly (p < 0.05) increased TLESR frequency in controls (1.6+/-0.3 to 3.5+/-1.0 per 20 min), GERD patients (1.2+/-0.3 to 3.1+/-0.5 per 20 min), and patients after fundoplication (0.5+/-0.1 to 1.8+/-0.6 per 20 min). Postfundoplication the number of TLESRs was significantly reduced (p < 0.05) both under fasting conditions and after air insufflation. The number of common cavities and belches after gastric air distension also was significantly reduced (p < 0.05) after fundoplication: 2.3+/-0.6 versus 4.7+/-0.4 in controls and 4.1+/-0.4 in GERD patients. About half of the common cavities occurred during TLESRs, and half during other mechanisms. An impaired ability to belch in daily life correlated with an impaired belching response during the test. An impaired ability to belch occurred only in patients with complete fundoplication and not in patients with partial fundoplication and was associated with a reduced number of common cavities after gastric air insufflation.

CONCLUSIONS

Short-lasting gastric air distension 1) provokes TLESRs but does not differentiate GERD patients from controls, 2) reveals impaired belching capacity in patients after complete fundoplication, and 3) shows that common cavities do not exclusively occur during TLESRs.

Influence of gender on proximal gastric motor and sensory function

OBJECTIVE

Gender-related differences have been demonstrated with regard to GI motility: gallbladder contraction, colonic transit, and gastric emptying are delayed in women. It is not known whether gender influences proximal gastric motility and perception.

METHODS

We have studied the influence of gender on proximal gastric motility and perception under fasting and postprandial conditions by retrospective analysis of data obtained in 99 healthy volunteers (42 men, 57 women) who participated in barostat studies performed according to standardized protocols at the Leiden University Medical Center (Leiden, The Netherlands) between 1996 and 2000.

RESULTS

Minimal distending pressure (MDP) was significantly higher in women than in men (respectively, 6.8+/-0.2 vs 5.5+/-0.2 mm Hg; p < 0.001). During stepwise pressure distensions pressure-volume curves were similar in both sexes after correction for MDP, whereas perception of fullness and abdominal pressure increased significantly (p < 0.05) more rapidly in women. Before the meal intragastric volumes (at MDP + 2 mm Hg) did not differ between sexes. After the meal gastric relaxation in the first 30 min did not differ in women and men (respectively, 186+/-23 ml and 140+/-32 ml). However, from 30 until 90 min after the meal a significantly (p < 0.05) delayed return of intragastric volume to basal was seen in women. Perception of postprandial nausea was significantly (p < 0.01) increased in women. Perception of postprandial fullness remained increased for a longer period of time in women.

CONCLUSIONS

Proximal gastric motility and perception are influenced by gender. Gender-related differences in postprandial proximal gastric motility and perception should be taken into account in barostat studies comparing patients with controls.

Comparison of ileoanal pouch and rectal function measured by barostat

The aim of this study was to compare pouch and rectal sensory and motor characteristics and to assess the influence of a meal on pouch tone and motility. Fifteen patients with an ileoanal J-pouch, with adequate pouch function and 12 healthy controls were studied. Visceral compliance was assessed using an electronic barostat by a pressure distension procedure, during which also sensitivity was scored by visual analog scales (VAS). The response to a meal was assessed during set pressure. Pouch and rectal compliance were not significantly different (9.3+/-0.7 vs 10.6+/-1.1 ml/mm Hg). VAS score for urge at 28 mm Hg was reduced in patients: 2.4+/-0.5 cm vs 4.7+/-0.9 cm in controls (P < 0.05). The postprandial decrease in intra-bag volume was more pronounced in patients (44+/-11%) than in controls (9+/-6%, P < 0.01). Postprandial phasic contractions were also more pronounced in patients. In conclusion, compliance is not significantly different between ileoanal pouch and rectum; differences in sensitivity reach significance only at high pressure. Significant differences were especially observed in the postprandial state with an increase in tone and frequency of phasic contractions in pouch patients.

Role of cholecystokinin in relaxation of the proximal stomach

Ingestion of a meal causes proximal gastric relaxation (accommodation). The magnitude of accommodation is related to the fat content of the meal. A role for cholecystokinin (CCK) has been suggested. However, under fasting conditions intravenous CCK to postprandial levels does not induce a similar accommodation. This study further explores the role of CCK in accommodation. A gastric barostat was used in eight healthy persons to study accommodation in response to a carbohydrate meal with intravenous CCK (CH-CCK), carbohydrate meal with intravenous placebo (CH-placebo) and a fat rich meal with intravenous placebo (FAT). VAS scores for satiety and plasma CCK levels were obtained. In the first postprandial hour the FAT meal induced a relaxation of 112 +/- 29 ml, the CH-CCK meal 49 +/- 36 ml and the CH-placebo meal 12 +/- 32 ml (FAT versus CH-placebo P = 0.03; FAT versus CH-CCK P = 0.09). In the second postprandial hour, intragastric bag volume returned to baseline with all meals. The FAT meal had the most pronounced effect with respect to satiety, CH-placebo the least. In the first postprandial hour, plasma CCK levels increased with the CH-CCK and FAT meals but not with the CH-placebo meal; in the second postprandial hour, levels remained elevated with the CH-CCK meal. It is concluded that a carbohydrate meal with exogenous CCK does not induce fundic relaxation, whereas a fat-rich meal (endogenous CCK) does, despite similar plasma CCK levels.

Analysis and surgical treatment of persistent dysphagia after Nissen fundoplication

BACKGROUND

After Nissen fundoplication, troublesome dysphagia develops in 5-10 per cent of patients. The mechanism of dysphagia has not been fully resolved, in spite of a number of studies focusing on oesophageal motility and lower oesophageal sphincter (LOS) dynamics. Tightness and length of the wrap have had considerable attention, without giving a fully satisfactory explanation of the pathophysiological mechanism.

METHODS

Eighteen patients with persistent dysphagia after Nissen fundoplication needing reoperation were studied. Eighteen patients, matched for age and sex, without dysphagia after Nissen fundoplication were used as controls. Reoperation consisted of conversion of a 360 degrees into a 270 degrees wrap. Barium swallow, endoscopy, oesophageal manometry and 24-h pH monitoring were performed before and after (re)operation.

RESULTS

Peristaltic amplitude, velocity and duration of contraction were not significantly influenced by operation. In 16 of 18 patients with dysphagia, LOS relaxation was incomplete and the residual relaxation pressure was significantly higher than that in the group without dysphagia (P < 0.01). No correlation was found between LOS pressure and peristaltic amplitude, nor between LOS pressure and ramp pressure in the distal oesophagus. After reoperation, basal LOS pressure decreased significantly (P < 0.01) and LOS relaxation was complete in all but three patients; residual relaxation pressure decreased (P < 0.01) and was significantly lower than that after uncomplicated Nissen fundoplication. In the latter group, LOS pressure, residual relaxation pressure and ramp pressure increased significantly after operation (P < 0.01).

CONCLUSION

A return to complete LOS relaxation and a decrease in residual relaxation pressure play an important role in resolving dysphagia.

Reproducibility of antroduodenal motility during prolonged ambulatory recording

Ambulatory recording of antroduodenal manometry is a novel technique with several advantages over standard stationary manometry recording. Although the feasibility of this technique in clinical practice has been demonstrated, reproducibility of antroduodenal motility recorded by means of ambulatory manometry has not been investigated. To test whether antroduodenal motility recorded by ambulatory manometry is reproducible, we performed two 24-h ambulatory antroduodenal manometry recordings in 18 healthy subjects according to an identical protocol with a 1-week interval. Motility was recorded with a five-channel solid-state catheter. Postprandial motility was recorded after consumption of two test meals and interdigestive motility was recorded nocturnally. Postprandial antroduodenal motor characteristics were identical between the separate recordings. The number and duration of nocturnal cycles of the interdigestive migrating motor complex were also in the same range. Phase III characteristics in general were not different between the two recordings. Only minor alterations were observed in the duration of phase III motor fronts with duodenal onset and in the number of interdigestive cycles concluded by duodenal onset phase III. Parameters obtained by qualitative analysis were comparable between the two recordings. The antroduodenal motility pattern, when measured by ambulatory recording with solid state catheters under standardized conditions, is very reproducible.

Effect of modified sham feeding and insulin-induced hypoglycemia on function of the proximal stomach

BACKGROUND/AIM

Animal experiments have shown that vagal cholinergic stimulation causes an increase in proximal gastric tone, but little is known about the effect of vagal stimulation on proximal gastric motor function in humans. Vagal cholinergic stimulation can be elicited by modified sham feeding (MSF) or by insulin-induced hypoglycemia. The aim of our study was to investigate the effect of MSF and insulin-induced hypoglycemia on the motor and sensory function of the proximal stomach in humans.

METHODS

Eight healthy volunteers participated in random order in three experiments: (A) control experiment, (B) MSF and (C) intravenous insulin injection. Intragastric volume was recorded with a barostat set at a constant preselected pressure level (MDP + 2 mm Hg). Pancreatic polypeptide (PP) secretion was measured as an indicator of cholinergic tone.

RESULTS

PP secretion increased significantly after both MSF (p<0.05) and insulin administration (p<0.01). No changes in intragastric volume were seen after MSF, while intragastric volume increased significantly in response to insulin-induced hypoglycemia when compared to control (290+/-43 vs. 148+/-24 ml; p<0.01). No differences in perception scores were seen between the three experiments.

CONCLUSIONS

Vagal cholinergic stimulation by MSF has no effect on the motor function of the proximal stomach, while insulin-induced hypoglycemia causes a relaxation of the proximal stomach.

Motor and sensory function of the rectum in different subtypes of constipation

BACKGROUND

It is not known whether evaluation of motor and sensory function of the rectum using a barostat may help to distinguish subtypes of constipation.

METHODS

Motor and sensory function of the rectum have been evaluated using a barostat in 14 patients with slow transit constipation (STC), 12 patients with constipation-predominant irritable bowel syndrome (IBS) and 18 healthy controls. First minimal distending pressure was determined, after which spontaneous adaptive relaxation of the rectum was monitored. Then a step-wise isobaric distension procedure was performed, during which symptom perception was determined. The distension was followed by a 90-min barostat procedure: for 30 min in the basal state followed by ingestion of a semi-liquid meal (postprandial state).

RESULTS

Minimal distending pressure was not different between both patient groups and controls, neither was compliance different between constipated patients and controls. The degree of spontaneous adaptive relaxation was in the same range in all groups. During distensions with high pressures, the perception of urge was significantly reduced in STC patients compared to IBS and controls, while the perception of pain was significantly increased in IBS versus STC and controls. Postprandially, a small decrease of rectal volume was only observed in the control group, but not in the patients.

CONCLUSIONS

Rectal motor characteristics are not different between patients with constipation-predominant IBS, patients with STC and healthy controls while during isobaric distensions, sensations of urge were reduced in STC and sensations of pain were increased in IBS. Rectal visceroperception testing may help distinguish groups of patients with different subtypes of constipation.

Effect of somatostatin on postprandial gallbladder relaxation

Although the inhibitory effect of somatostatin (SST) on gallbladder contraction is well known, the influence of SST on gallbladder motility during the late postprandial or relaxation phase has not been studied. We therefore investigated the effect of SST on gallbladder relaxation and gut hormone release during the late postprandial phase. Eight healthy volunteers participated in two experiments performed in random order during continuous infusion of either SST or saline (placebo) starting 2 h after meal ingestion. At regular intervals, gallbladder volumes were measured (ultrasonography) and blood samples were taken for determination of plasma cholecystokinin (CCK), pancreatic polypeptide (PP), peptide YY (PYY) and neurotensin levels (radioimmunoassay). Postprandial gallbladder contraction was similar in both experiments: 68 +/- 4% vs. 66 +/- 4%. During SST infusion, postprandial gallbladder contraction was significantly (P<0.01) reduced (2874 +/- 813% *240 min) compared with saline (9391 +/- 1595% *240 min). Plasma CCK, PP, PYY and neurotensin levels were in the same range in the early postprandial phase but were significantly reduced during SST infusion compared with placebo (late postprandial phase). Plasma levels of CCK correlated with gallbladder volumes during both the contraction and relaxation phase (r=0.68, P=0.01 and r=0.61, P=0.008, respectively). SST enhances gallbladder relaxation and reduces hormone secretion in the late postprandial phase. The results point to an association between CCK and gallbladder volume not only during the postprandial contraction phase but also during the relaxation phase.

Effect of intraduodenal and intravenous amino acids on proximal gastric motor function in man

The present study was performed to investigate the effect of amino acids during the intestinal and postabsorptive phase of digestion on proximal gastric motor function measured with an electronic barostat. Eight healthy volunteers participated in three experiments performed during continuous infusion of: (1) intravenous and intraduodenal saline, (2) intraduodenal amino acids, and (3) intravenous amino acids. Both intraduodenal and intravenous amino acids induced gastric relaxation and increased gastric compliance. Only during intraduodenal amino acids did plasma CCK levels increase significantly. Correlation between intragastric volume measurements (with pressure set at MDP + 2 mm Hg) and plasma CCK levels was 0.90 (P < 0.001) during the early intestinal phase. Relaxation of the proximal stomach is related to plasma CCK in the early intestinal phase, whereas in the postabsorptive phase of amino acids other mechanisms play a role in proximal gastric relaxation.

Double-blind, placebo-controlled study of oral calcitriol for the treatment of localized and systemic scleroderma

BACKGROUND

Various treatments including corticosteroids, nonsteroidal anti-inflammatory drugs, D-penicillamine, interferon gamma, cyclosporine, and cytostatic drugs have been used with limited success in both morphea and systemic sclerosis (SSc).

OBJECTIVE

We investigated the effect of treatment with oral calcitriol in patients with localized or systemic scleroderma.

METHODS

A randomized, double-blind, placebo-controlled study of 9 months' duration with a 6-month follow-up was performed at the Department of Dermatology. A total of 27 patients (7 patients with SSc and 20 with morphea) were selected on a minimal skin score of 3 for patients with morphea and 12 for those with SSc. Each patient received calcitriol (0.75 microg/day for 6 months plus 1.25 microg/day for 3 months) or placebo for 9 months. Efficacy parameters included skin score, measurement of serum markers of collagen synthesis and degradation and, additional for the patients with SSc, oral aperture measurements, lung function studies, and esophagus motility.

RESULTS

The skin score in patients with morphea after 9 months' treatment showed no significant difference between the placebo and calcitriol groups (mean percentage reduction [SD] in skin score in the placebo group was -29.3 [57.9]; in the calcitriol group it was -19.4 [46.6]). The small group of patients with SSc was inadequate to allow us to draw any conclusions regarding efficacy. No significant change was found in the serum markers of collagen metabolism.

CONCLUSION

In this study calcitriol was not more effective than placebo in patients with morphea. Because of the small group of patients with SSc treated, no conclusions regarding efficacy in SSc can be drawn.

Gallbladder motility in Crohn disease: influence of disease localization and bowel resection

BACKGROUND

Patients with Crohn disease (CD) have an increased risk of developing gallstones. Among other factors, gallbladder motility may have a role in the pathogenesis of gallstone formation. We have evaluated whether gallbladder motor function is affected in Crohn disease with special emphasis on the influence of disease localization and previous bowel resection.

METHODS

Thirty-seven patients (20 females and 17 males, age 36 +/- 2 years) with inactive Crohn disease (CDAI < 150) were studied: 15 patients after ileocecal resection and 22 non-operated patients; 12 had small bowel disease and 10 had large bowel disease. Nineteen healthy subjects (10 female; 9 male, age 30 +/- 2 years) served as controls. Gallbladder volumes were measured in the fasting state and at regular intervals for 2 h after ingestion of a solid meal (780 kcal). Blood samples were drawn at regular intervals for determination of cholecystokinin (CCK) and peptide YY (PYY).

RESULTS

Fasting gallbladder volumes were significantly (P < 0.05) reduced in patients with large bowel disease (20.8 +/- 2.1 ml) or after ileocecal resection (18.3 +/- 2.4 ml) compared to patients with small bowel disease (28.0 +/- 2.1 ml) and controls (27.2 +/- 1.8 ml). Fasting plasma CCK levels were significantly (P < 0.05) higher in patients with large bowel disease or after ileocecal resection compared to patients with small bowel disease and controls. Postprandial gallbladder emptying and endogenous plasma CCK and PYY secretion in patients with Crohn disease were not different from controls.

CONCLUSIONS

Fasting gallbladder volume is decreased and fasting plasma CCK levels are increased in patients with Crohn disease of the large bowel and patients after ileocecal resection. Postprandial gallbladder motility, CCK and PYY release were not affected in patients with Crohn disease.

Effect of bombesin on esophageal motility in humans

We have investigated the effect of bombesin on esophageal motility and explored the mechanism of action of bombesin. Eight healthy subjects were studied in random order during intravenous administration of (1) bombesin, (2) bombesin + vagal cholinergic receptor blockade with atropine and (3) bombesin + somatostatin. Lower esophageal sphincter pressure (LESP) and esophageal body motility were recorded continuously by Dent-sleeve manometry. Bombesin significantly (p < 0.01) increased LESP from 20 +/- 2 mmHg to 43 +/- 6 mmHg. Neither atropine nor somatostatin significantly reduced the bombesin-induced increases in LESP. Bombesin significantly (p<0.05) increased peristaltic wave amplitude (from 61 +/- 4 to 105 +/- 9 mmHg) and duration (from 2.9 +/- 0.2 to 4.8 +/- 0.3 s) in the mid and distal part of the esophagus. Neither atropine nor somatostatin significantly reduced the esophageal body motor response to bombesin. In conclusion (1) bombesin significantly increases LESP and affects esophageal body motility by increasing peristaltic wave amplitude and duration and (2) the effect of bombesin on esophageal motility is not dependent on vagal cholinergic mechanisms and is not mediated by the action of gastrointestinal hormones released by bombesin.

Effects of very long chain versus long chain triglycerides on gastrointestinal motility and hormone release in humans

Fish oil (a very long chain triglycerides, VLCT) has received much attention because of its favorable metabolic properties; however, its effect on gastrointestinal function has not been studied. We investigated the effects of intraduodenally administered VLCT on gut-hormone release [cholecystokinin (CCK), neurotensin, peptide YY (PYY)], gallbladder emptying, antroduodenal motility, and small bowel transit time (SBTT) in comparison to intraduodenal administration of saline and long chain triglycerides (LCT, corn oil) in nine healthy volunteers. Gallbladder contraction duration was significantly shorter after VLCT than after LCT (138 +/- 16 min vs 233 +/- 38 min, P < 0.05). Both fats induced a fed motility pattern, while SBTT was not significantly altered. CCK secretion was significantly reduced after VLCT compared to LCT (36 +/- 12 pM x 120 min vs 78 +/- 15 pM x 120 min, P < 0.05), whereas PYY and neurotensin release were not significantly different. In conclusion, effects of triglycerides on CCK and gallbladder motility appear to be chain-length dependent, in contrast to the effects on distal gut-hormone release and intestinal motility and transit, which appear to be chain-length independent.

Effect of somatostatin on lower esophageal sphincter characteristics in man

BACKGROUND

Somatostatin (SST) is known for its inhibitory effect on the gastrointestinal tract. Transient lower esophageal sphincter relaxations (TLESR), low or absent LES pressure (LESP) and swallow-induced LES relaxations are the most important reflux mechanisms.

METHODS

We have studied the effect of somatostatin on lower esophageal sphincter (LES) characteristics in man. Nine healthy volunteers participated in four experiments performed in random order and double-blind during continuous infusion of somatostatin (250 microg/h) or saline (control) under fasting and postprandial conditions. Esophageal motility was measured with sleeve manometry combined with pH metry.

RESULTS

Under fasting conditions LESP was not influenced by somatostatin. Ingestion of the carbohydrate meal significantly (P < 0.01) decreased LESP. During continuous somatostatin infusion the postprandial decrease in LESP did not occur; LESP was even significantly (P < 0.05) increased over basal levels. Somatostatin did not significantly influence TLESR frequency, neither under basal conditions, nor postprandially. The residual pressure during swallow-induced LES relaxation was significantly (P < 0.05) increased by somatostatin.

CONCLUSION

In humans somatostatin prevents postprandial reduction in LESP, does not affect TLESR, but inhibits swallow-induced LES relaxation.

Proximal and distal gut hormone secretion in slow transit constipation

BACKGROUND

It has been suggested that slow transit constipation might be part of a panenteric disorder. Gastrointestinal peptides are involved in regulation of motility.

DESIGN

In the present study we have evaluated whether plasma levels of proximal and distal gut hormones in the fasting state, and for 120 min after a solid meal in 29 patients with slow transit constipation are different from those obtained from 29 healthy controls. Plasma levels of the gut hormones cholecystokinin, gastrin, pancreatic polypeptide, motilin, neurotensin and peptide YY were determined using sensitive radioimmunoassays. In the patient group, oro-caecal transit time was determined by means of the hydrogen breath test on a separate test day. The results of transit were related with postprandial hormone secretion.

RESULTS

Fasting plasma levels of cholecystokinin and pancreatic polypeptide were significantly (P < 0.05) increased in constipated patients. Postprandially, secretion of pancreatic polypeptide and cholecystokinin was significantly (P < 0.05) increased in the patients, while secretion of peptide YY was significantly (P < 0.05) reduced. Plasma motilin levels were not different between patients and controls. Altered postprandial hormone secretion was mainly observed in constipated patients with prolonged oro-caecal transit time.

CONCLUSIONS

In patients with slow transit constipation, fasting and postprandial secretion of proximal gut hormones apart from motilin is increased and of distal gut hormones decreased, especially in those with severely delayed intestinal transit.

Effects of hyperglycaemia and hyperinsulinaemia on proximal gastric motor and sensory function in humans

During acute hyperglycaemia, gastric emptying is delayed and the compliance of the proximal stomach is increased significantly. It is not known whether the effect of hyperglycaemia on proximal gastric motor function in healthy volunteers results from endogenous hyperinsulinaemia. Therefore we studied the effects of acute hyperglycaemia and hyperinsulinaemia on proximal gastric function, measured using an electronic barostat. Eight healthy volunteers were studied on three separate occasions during: (a) normoglycaemia, (b) hyperglycaemic hyperinsulinaemic clamping, and (c) euglycaemic hyperinsulinaemic clamping. Gastric compliance was significantly (P<0.01) increased during hyperglycaemia (44+/-5 ml/mmHg), and also during hyperinsulinaemia (38+/-4 ml/mmHg), compared with during normoglycaemia (31+/-3 ml/mmHg). During pressure distension, sensations of fullness were greater during hyperglycaemia and during hyperinsulinaemia compared with controls. At a set pressure of minimal distension pressure +2 mmHg, the intrabag volume was significantly higher during hyperglycaemia (292+/-36 ml; P<0.05), but not during hyperinsulinaemia (161+/-35 ml), compared with during normoglycaemia (129+/-10 ml). Postprandial relaxation was significantly (P<0.01) decreased during hyperglycaemia (93+/-64 ml) and hyperinsulinaemia (101+/-64 ml) compared with normoglycaemia (224+/-56 ml). Thus not only hyperglycaemia, but also hyperinsulinaemia, influences proximal gastric compliance, postprandial relaxation and symptom perception.

The osmotic laxative magnesium sulphate activates the ileal brake

BACKGROUND

Alterations in gastrointestinal motility and hormone secretion, especially activation of the ileal brake, have been documented in malabsorption.

AIM

To investigate whether artificially-induced accelerated small intestinal transit activates the ileal brake mechanism.

METHODS

Eight healthy volunteers (four female, four male; age 21 +/- 3 years) participated in four experiments: (a) meal with either oral magnesium sulphate (MgSO4) or placebo; and (b) fasting with either oral MgSO4 or placebo. Antroduodenal motility was recorded by perfusion manometry. Duodenocaecal transit time was determined by the lactulose H2 breath test. Gall-bladder volume was measured by ultrasound at regular intervals, and blood samples were drawn for determination of cholecystokinin and peptide YY (RIA). Twenty-four hour faecal weight and fat excretion were determined.

RESULTS

MgS04 significantly accelerated duodenocaecal transit time and increased faecal fat and weight in all subjects. MgSO4 significantly delayed the reoccurrence of phase III and affected antroduodenal motility during fasting but not after meal ingestion. Postprandial gall-bladder relaxation and postprandial peptide YY release were significantly increased during the MgSO4 experiment compared to placebo.

CONCLUSIONS

The osmotic laxative MgS04 accelerates intestinal transit both in the fasting and fed state. MgS04 activates the ileal brake mechanism only in the fed state, with peptide YY release and inhibition of gall-bladder emptying.

Limited influence of pouch function on quality of life after ileal pouch-anal anastomosis

BACKGROUND/AIMS

Despite a high frequency of pouch function disorders, most patients are satisfied with the outcome of ileo-anal pouch surgery. Aims of this study were: 1) To assess the influence of pouch function on quality of life and, 2) to determine which aspects of pouch dysfunction affect quality of life the most.

METHODOLOGY

Questionnaires, addressing current pouch function and quality of life (Rand-36, GIQLI), were sent to all (53) patients with intact ileo-anal pouches, operated on between 1987 and 1997 in our center.

RESULTS

Thirty-six of 53 patients responded. Compared to reference data, Rand-36 scores for role-limitations based on a physical problem, vitality and general health perception were significantly diminished (P < 0.01). Physical and social functioning were normal. The GIQLI score was slightly decreased (111.7 vs. 125.8, P < 0.01). Overall pouch function did not correlate with the overall Rand-36 score, but correlated well with the overall GIQLI score (r = -0.47). Both quality of life scores were diminished mainly by the night-time stool frequency.

CONCLUSIONS

1) Quality of life after IPAA, as measured with validated questionnaires, is only slightly decreased; 2) the GIQLI questionnaire is more sensitive to pouch dysfunction than the Rand-36; 3) night-time stool frequency influences quality of life the most.

Effect of L-arginine on lower oesophageal sphincter motility in man

OBJECTIVE

Inhibitory responses of the lower oesophageal sphincter (LOS) are mediated via an L-arginine/nitric oxide (NO) pathway. L-arginine is known as the precursor of NO. We have studied the effect of intravenous L-arginine on LOS motility in man.

DESIGN

Twelve healthy subjects participated in a double-blind, placebo-controlled randomized study.

METHODS

We investigated the effect of continuous infusion of L-arginine (500 mg/kg body weight/120 min) in six subjects under fasting conditions. Six other subjects were studied under postprandial conditions. LOS pressure (LOSP), swallow-induced LOS relaxations and transient lower oesophageal sphincter relaxations (TLOSR) were measured with sleeve manometry combined with pH metry. The meal consisted of a carbohydrate-high fat meal. Blood samples were taken before and after administration of L-arginine or saline to determine plasma levels of amino acids, cholecystokinin and gastrin.

RESULTS

Plasma levels of arginine and citrulline significantly (P < 0.05) increased during L-arginine infusion. L-arginine did not affect plasma hormone levels. Under fasting conditions, LOSP and TLOSR were not influenced by L-arginine. Ingestion of the carbohydrate-high fat meal significantly decreased LOSP. L-arginine did not significantly influence TLOSR frequency, either under fasting conditions or postprandially.

CONCLUSIONS

These results suggest that in humans under fasting or postprandial conditions intravenous infusion of L-arginine does not influence LOS motility.

Prospective study of the effect of laparoscopic hemifundoplication on motor and sensory function of the proximal stomach

BACKGROUND

Some 30 per cent of patients develop dyspeptic symptoms following antireflux surgery. These symptoms may result from alterations in the motor and sensory function of the proximal stomach.

METHODS

Proximal gastric motor and sensory function was studied with an electronic barostat in 12 patients with reflux who underwent laparoscopic hemifundoplication. In addition, 24-h pHmetry, gastric emptying (scintigraphy) and vagus nerve integrity (pancreatic polypeptide response to hypo-glycaemia) were assessed. Fifteen healthy volunteers served as controls.

RESULTS

Laparoscopic hemifundoplication significantly decreased total acid exposure time (P < 0.05). Vagus nerve function remained intact in all but one patient. The mean(s.e.m.) lag phase for emptying of solids was significantly shorter after operation than before (15(3) versus 21(3) min; P < 0.05). Proximal gastric compliance was not significantly different before and after fundoplication. However, mean(s.e.m.) postprandial relaxation was significantly reduced (P < 0.05) after hemifundoplication compared with the value before operation (3341(1105) versus 12 763(3616) ml over 90 min) and in controls (14 567(2358) ml over 90 min). Postprandial fullness was significantly increased after hemi-fundoplication (P < 0.05). Postprandial gastric relaxation correlated with the lag phase for emptying of solids (r = 0.55, P < 0.02).

CONCLUSION

After hemifundoplication, proximal gastric compliance is not altered but postprandial relaxation is impaired and associated with sensations of fullness and shorter duration of the lag phase for emptying of solids.

Antroduodenal motility in chronic pancreatitis: are abnormalities related to exocrine insufficiency?

In patients with chronic pancreatitis (CP) the relation among exocrine pancreatic secretion, gastrointestinal hormone release, and motility is disturbed. We studied digestive and interdigestive antroduodenal motility and postprandial gut hormone release in 26 patients with CP. Fifteen of these patients had pancreatic insufficiency (PI) established by urinary para-aminobenzoic acid test and fecal fat excretion. Antroduodenal motility was recorded after ingestion of a mixed liquid meal. The effect of pancreatic enzyme supplementation was studied in 8 of the 15 CP patients with PI. The duration of the postprandial antroduodenal motor pattern was significantly (P < 0.01) prolonged in CP patients (324 +/- 20 min) compared with controls (215 +/- 19 min). Antral motility indexes in the first hour after meal ingestion were significantly reduced in CP patients. The interdigestive migrating motor complex cycle length was significantly (P < 0.01) shorter in CP patients (90 +/- 8 min) compared with controls (129 +/- 8 min). These abnormalities were more pronounced in CP patients with exocrine PI. After supplementation of pancreatic enzymes, these alterations in motility reverted toward normal. Digestive and interdigestive antroduodenal motility are abnormal in patients with CP but significantly different from controls only in those with exocrine PI. These abnormalities in antroduodenal motility in CP are related to maldigestion.

[Gastro-intestinal surgery and gastroenterology. V. Chronic pancreatitis: gastroenterologic aspects]

Chronic pancreatitis causes irreversible damage to the pancreatic parenchyma and ultimately leads to exo- and endocrine insufficiency. In the Western world, alcohol is the main cause of chronic pancreatitis; part of the patients with idiopathic or alcoholic pancreatitis conceivably have a raised sensitivity to the toxic effects of alcohol because of a certain genetic predisposition. The most striking symptom, severe recurrent or persistent pain is often difficult to manage. Various forms of imaging examination provide complementary information on lesions of the pancreatic parenchyma, the pancreatic duct, the bile ducts and adjacent structures; ultrasonoscopy is the technique of first choice in case of suspicion of a pancreatic disorder. Endoscopic therapies are booming: sphincterotomy, calculus extraction, insertion of an endoprosthesis in the pancreatic duct and drainage of pseudocysts (transpapillary or through the jejunum or stomach).

Prolonged ambulatory recording of antroduodenal motility in slow-transit constipation

BACKGROUND

Slow-transit constipation may be part of a pan-enteric motor disorder. To test this hypothesis 24-h ambulatory antroduodenal manometry was performed and orocaecal transit time determined in patients with slow-transit constipation and in healthy controls.

METHODS

Antroduodenal motility was recorded with a five-channel solid-state catheter. Postprandial motility was recorded after consumption of two standardized test meals and interdigestive motility was recorded nocturnally. Manometry tracings were analysed for quantitative and qualitative abnormalities. Orocaecal transit time was determined by means of the lactulose hydrogen breath test.

RESULTS

Postprandial motility was no different between patients and controls. However, some minor changes of interdigestive motility were observed. The proportion of phase II activity of the nocturnal cycles of the interdigestive migrating motor complex was increased in patients while phase I activity was decreased. The total number of observed phase III fronts was no different in patients and controls, although the number of phase III fronts with antral onset was decreased. Furthermore, the amplitude of phase III activity of duodenal onset was also decreased. Specific motor abnormalities such as retrograde propagation of phase III fronts were more frequent in patients. Orocaecal transit time was delayed in patients.

CONCLUSION

In patients with slow-transit constipation, orocaecal transit time is delayed but antro- duodenal motility is generally well preserved with only minor alterations. Presented as a poster to the Digestive Disease Week meeting in New Orleans, Louisiana, USA, May 1998, and published in abstract form as Gastroenterology 1998; 114: A820

Surgical treatment for recurrent gastro-oesophageal reflux disease after failed antireflux surgery

BACKGROUND

Recurrent or persistent symptoms occur in 10-15 per cent of patients after antireflux surgery. Failure of surgery is not uniform in its presentation. The cause of failure is not easily detected and even harder to treat. Different approaches have been proposed and few reports are available on the objective and subjective outcome of reoperation.

METHODS

This study focuses on 30 patients (16 men and 14 women; age range 20-69 years) with recurrent symptomatic gastro-oesophageal reflux disease (GORD) resistant to medical treatment. In all patients reoperation was by the Belsey Mark IV antireflux operation. A clinical history, endoscopy and oesophageal manometry were obtained in all patients, and 24-h pH monitoring was performed in 27 of 30 before and in most patients after the Belsey procedure.

RESULTS

Symptomatic improvement was reported in 24 of 30 patients. Oesophagitis (present before operation in 19 patients) was cured or remained absent in 24 of 30 patients, stabilized in one, improved in four and deteriorated in one. Relief of symptoms combined with absence of oesophagitis was obtained in 21 of 30 patients, with concomitant normalization of the 24-h pH profile in 11 of 22 patients. The median basal lower oesophageal sphincter (LOS) pressure increased significantly from 6. 9 to 9.0 mmHg (P < 0.01). Redo surgery had no effect on oesophageal body motility.

CONCLUSION

Reoperation performed for documented recurrent GORD had a good and lasting effect on symptoms, on oesophagitis (both in 24 of 30 patients) and on the combination of both (21 of 30). In these patients reoperation increased basal LOS pressure and decreased reflux time. Overall, the results approximate to those of primary operation.

Onset of action during on-demand treatment with maalox suspension or low-dose ranitidine for heartburn

AIM

To compare the onset of action of the local antacid Maalox and the systemic H2-antagonist ranitidine, during 'on demand' ambulant treatment of a single heartburn episode, using a randomized, parallel group, double-blind, double-dummy design.

METHODS

Subjects with self-perceived heartburn without known gastrointestinal disease or interfering treatments were selected with questionnaires. The study was performed unsupervised, whenever heartburn required medication. An electronic patient diary gave instructions when to take study medication, and provided visual analogue scales and five-item relief ratings for heartburn, at frequent time intervals activated by an alarm-clock.

RESULTS

After a study of the natural history of heartburn and the feasibility of the study procedures in 23 patients, 49 subjects took Maalox and 45 ranitidine. Half of these experienced meaningful heartburn relief within 19 min after Maalox, and within 70 min after ranitidine. One hour after intake, the average heartburn relief score was 3.43 in the Maalox group and 3.04 in the ranitidine group (3 means 'slight improvement' and 4 'strong improvement'). Heartburn was similar in both groups after 3 h.

CONCLUSIONS

Maalox provides faster relief of heartburn than ranitidine. Heartburn can be assessed frequently and reliably under ambulant conditions using an electronic patient diary.

Medium chain triglycerides activate distal but not proximal gut hormones

BACKGROUND AND AIMS

Compared to long chain triglycerides (LCT), medium chain triglycerides (MCT) are considered an attractive caloric source in malabsorptive diseases because of their favorable physico-chemical characteristics. The use of MCTis, however, limited by the occurrence of gastrointestinal symptoms such as diarrhoea. We have, therefore, investigated the effects of MCT and LCT on proximal (cholecystokinin; CCK) and distal (peptide YY; PYY) gut hormone secretion.

METHODS

Eight healthy volunteers participated in four experiments performed in random order during continuous intraduodenal administration for 360 min of a) saline (control); b) LCT15 mmol/h; c) MCT15mmol/h (equimolar); d) MCT 30 mmol/h (equicaloric). Plasma CCK and PYY were determined at regular intervals (radioimmunoassay). Duodenocecal transit (DCTT) was measured by lactulose H(2)breath test.

RESULTS

DCTT during LCT (105 +/- 11 min) was not significantly different from saline (111 +/- 10 min). Both low dose MCT (54 +/- 5 min) and high dose MCT (61 +/- 6 min) significantly accelerated DCTT (P< 0.05). Plasma CCK increased significantly (P< 0.05) during LCT but not during MCT or saline. PYY increased significantly (P< 0.05) not only during LCT, but also during low and high dose MCT but not during saline.

CONCLUSIONS

Intraduodenal MCTs a) accelerate intestinal transit; b) do not stimulate CCK release; c) but stimulate release of the distal gut hormone PYY. These results suggest that MCTs are not rapidly absorbed in the proximal gut but probably reach the ileocolonic region and stimulate PYY release.

Does jejunal feeding activate exocrine pancreatic secretion?

BACKGROUND

The upper small bowel is of pivotal importance for the stimulation of exocrine pancreatic secretion in response to a meal. We hypothesize that more distal delivery of nutrients into the small intestine will result in less activation of pancreatic secretion.

MATERIALS AND METHODS

Eight healthy subjects (3 male, 5 female; age 23 +/- 1 years) participated in two experiments, performed in random order. Subjects were intubated with a 4-lumen tube. Duodenal outputs of pancreatic enzymes and bilirubin were measured by aspiration using a recovery marker. The distal opening was used for continuous administration of a mixed liquid meal and located at either the ligament of Treitz or 60 cm further distally. Gallbladder volume was measured and blood samples were drawn for determination of gastrointestinal hormones. The duration of each experiment was 4 h; with 1 h fasting and 3 h continuous administration of nutrients.

RESULTS

During proximal jejunal feeding, pancreatic enzyme output increased significantly over basal levels. No significant increase over basal levels was observed during distal jejunal feeding. Bilirubin output and gallbladder contraction were significantly (P < 0.05) reduced during distal compared to proximal jejunal feeding. No significant differences were found in plasma levels of CCK, PYY and neurotensin between proximal and distal jejunal feeding.

CONCLUSION

Continuous feeding in the distal jejunum does not stimulate exocrine pancreatic secretion but maintains gallbladder contraction, although to a lesser extent. These effects are not related to hormonal changes but probably reduced activation of the enteropancreatic reflexes.

Effect of gastrin on proximal gastric motor function in humans

The present study was performed to investigate the effect of gastrin on proximal gastric motor and sensory function. Ten healthy volunteers participated in three experiments performed in random order during: (A) continuous intravenous infusion of saline (control) or (B) gastrin (15 pmol kg-1 h-1) reaching postprandial serum gastrin levels or (C) gastrin infusion (15 pmol kg-1 h-1) preceded by acute acid inhibition with intravenous omeprazole. Proximal gastric function was evaluated using a barostat with stepwise pressure and volume distensions and volume measurements during set pressure (MDP + 2 mmHg). Gastrin significantly increased the intragastric volume compared to control during MDP + 2 mmHg (276 +/- 39 mL vs. 159 +/- 9 mL; P < 0.01) and reduced phasic slow volume wave frequency (from 1.4 +/- 0.1 to 0.7 +/- 0.1 per min; P < 0.01). During isobaric distensions gastrin increased gastric compliance (42 +/- 4 mL mmHg-1 vs. 31 +/- 3 mL mmHg-1; P < 0.05). These effects of gastrin infusion were completely abolished by pretreatment with omeprazole. Symptom perception decreased during gastrin infusion and was more dependent on pressure and wall tension than on volume.

IN CONCLUSION

gastrin may have a role in regulating proximal gastric mechanics by inducing fundic relaxation and increasing gastric wall compliance. The effect of gastrin is dependent on acid secretion.

Long-term results of octreotide-therapy in severe dumping syndrome

OBJECTIVE

Little is known about the long-term results of octreotide therapy in dumping syndrome. We report the results of an open study including 20 patients with severe dumping symptoms after gastric surgery treated with octreotide between 1987 and 1997 at the Leiden University Medical Centre.

DESIGN

Patient selection was based on (1) the results of a dumping provocation test and (2) symptoms that were refractory to other therapeutic measures. At regular intervals the presence of dumping symptoms was evaluated together with measurement of body weight and faecal fat excretion.

RESULTS

Mean follow-up was 37 +/- 9 months (range 1-107 months). Doses of octreotide ranged from 25 to 200 microg/day. Initial relief of symptoms was achieved in all subjects, but after three months of therapy symptom relief persisted in 80% of patients. Mean body weight increased by 2.4 +/- 1.2 kg despite a significant increase in faecal fat excretion from 10 +/- 2 g/24 h to 24 +/- 3 g/24 h. Reasons for discontinuation of therapy were diminished efficacy in the longer term in 4 patients and side-effects in 7 patients. Biliary complications were encountered in 3 patients.

CONCLUSIONS

Self-administration of octreotide proves an effective symptomatic treatment of severe dumping, even on the long-term. Its use is frequently limited by the occurrence of side-effects.

The role of the barostat in human research and clinical practice

BACKGROUND

The barostat is a recently developed device used to study the physiology and pathophysiology of the motor and sensory functions of the gastrointestinal tract. It can monitor volume changes while maintaining a set constant pressure and deliver controlled distensions of gastrointestinal organs. Simultaneously, motility and visceral perception may be assessed. The barostat has contributed to the understanding of physiological processes in the gastrointestinal tract with regard to regulation of tone, compliance, enteric reflexes, sensation and processing of signals to and from the gut. In addition, the barostat has been used to study various gastrointestinal disorders. In functional bowel disorders, objective abnormalities in visceral sensitivity and enteric reflexes have been demonstrated. Numerous other diseases, gastrointestinal in origin as well as systemic diseases affecting the gut, have been studied. In the near future, the barostat may become a clinically useful tool for the objective diagnosis of motor and sensitivity disorders of the gut and for monitoring the effectiveness of therapy.

Cholecystokinin secretion in patients with chronic pancreatitis and after different types of pancreatic surgery

Cholecystokinin (CCK) secretion may be affected in patients with chronic pancreatitis (CP), but little is known on the effect of pancreatic surgery on CCK secretion. We measured CCK secretion (radioimmunoassay, RIA) in response to bombesin infusion (100 ng/kg/20 min) for 120 min to test CCK secretory capacity, to ingestion of a liquid diet (400 kcal) for 120 min, and in response to a solid fat-rich meal (500 kcal) for 120 min. These studies were performed in 45 patients with CP (25 with exocrine insufficiency), 15 patients after duodenum-preserving pancreatic head resection (DPRHP), 18 patients after the Whipple operation, 12 patients after distal pancreatectomy (DP), and 35 control subjects. In CP patients, the CCK secretory capacity was preserved, but the postprandial CCK response was reduced, depending on meal composition and the presence of exocrine insufficiency. In patients after Whipple's operation, CCK secretory capacity and postprandial CCK secretion were significantly (p < 0.05) reduced. In patients after DPRHP, CCK secretory capacity was not affected, but the postprandial CCK response was significantly (p < 0.05) reduced, depending on meal composition and the presence of exocrine insufficiency. In patients after DPRHP, fasting plasma CCK levels were significantly (p < 0.01) increased, pointing to the absence of feedback inhibition on CCK secretion by intraluminal enzymes. After DP, the CCK secretory capacity was not affected.

IN CONCLUSION

alterations in CCK secretion are observed in patients with chronic pancreatitis and after pancreatic surgery. These alterations are related not only to the disease process (exocrine insufficiency) but also to the type of surgery and type of stimulus.