[Probiotic prophylaxis in patients with predicted severe acute pancreatitis: a randomised, double-blind, placebo-controlled trial]. / Probioticaprofylaxe bij voorspeld ernstige acute pancreatitis: een gerandomiseerde, dubbelblinde, placebogecontroleerde trial.

OBJECTIVE: To evaluate whether enteral prophylaxis with probiotics in patients with predicted severe acute pancreatitis prevents infectious complications. DESIGN: Multicentre, randomised, double-blind, placebo-controlled trial. METHOD: A total of 296 patients with predicted severe acute pancreatitis (APACHE II score > or = 8, Imrie score > or = 3 or C-reactive protein concentration > 150 mg/l) were included and randomised to one of two groups. Within 72 hours after symptom onset, patients received a multispecies preparation of probiotics or placebo given twice daily via a jejunal catheter for 28 days. The primary endpoint was the occurrence of one of the following infections during admission and go-day follow-up: infected pancreatic necrosis, bacteraemia, pneumonia, urosepsis or infected ascites. Secondary endpoints were mortality and adverse reactions. The study registration number is ISRCTN38327949. RESULTS: Treatment groups were similar at baseline with regard to patient characteristics and disease severity. Infections occurred in 30% of patients in the probiotics group (46 of 152 patients) and 28% of those in the placebo group (41 of 144 patients; relative risk (RR): 1.1; 95% CI: 0.8-1.5). The mortality rate was 16% in the probiotics group (24 of 152 patients) and 6% (9 of 144 patients) in the placebo group (RR: 2.5; 95% CI: 1.2-5.3). In the probiotics group, 9 patients developed bowel ischaemia (of whom 8 patients died), compared with none in the placebo group (p = 0.004). CONCLUSION: In patients with predicted severe acute pancreatitis, use of this combination of probiotic strains did not reduce the risk of infections. Probiotic prophylaxis was associated with a more than two-fold increase in mortality and should therefore not be administered in this category of patients.

The use of animal models to study bacterial translocation during acute pancreatitis.

Infection of pancreatic necrosis with intestinal flora is accepted to be a main predictor of outcome during severe acute pancreatitis. Bacterial translocation is the process whereby luminal bacteria migrate to extraintestinal sites. Animal models were proven indispensable in detecting three major aspects of bacterial translocation: small bowel bacterial overgrowth, mucosal barrier failure, and disturbed immune responses. Despite the progress made in the knowledge of bacterial translocation, the exact mechanism, origin and route of bacteria, and the optimal prophylactic and treatment strategies remain unclear. Methodological restrictions of animal models are likely to be the cause of this uncertainty. A literature review of animal models used to study bacterial translocation during acute pancreatitis demonstrates that many experimental techniques per se interfere with intestinal flora, mucosal barrier function, or immune response. Interference with these major aspects of bacterial translocation complicates interpretation of study results. This paper addresses these and other issues of animal models most frequently used to study bacterial translocation during acute pancreatitis.

A new intelligent distension system for hollow organs.

Controlled distension of hollow organs is an accepted technique for generating reproducible visceral stimuli. We have constructed a new, flexible and intelligent distension system in which discomfort, pain and autonomic responses are recorded online. These responses can be fed back into the system in a regulatory loop and be used to shape the distension paradigm. Consequently, it is possible to take all subjects to a state of equal, although subjective, level of discomfort or pain, even though pressure, tension and volume might be totally different. By using a variable airflow, this new distension system can be effectively used in all kinds of paradigms, e.g. phasic, tonic, or ramp distensions or customized combinations of them. The system can be used to control pressure, volume or tension. A refinement of the system is that it is possible to automatically change the controlled entity during a distension, e.g. from an isobaric ramp directly into an isovolumetric tonic phase. Furthermore, the distension device allows double distensions with independent distension paradigms.

[Potential role for probiotics in the prevention of infectious complications during acute pancreatitis]. / Potentiële rol voor probiotica bij de preventie van infectieuze complicaties tijdens acute pancreatitis.

Acute pancreatitis has a high mortality in case of secondary infection of (peri-)pancreatic necrosis. Bacterial translocation is held responsible for the majority of these infectious complications of severe acute pancreatitis. Prophylactic strategies should therefore be directed at the three most important pathophysiological mechanisms of bacterial translocation: disturbed small-bowel motility and bacterial overgrowth, failure of the mucosal barrier function and a disturbed response of the immune system. In-vitro studies and research in experimental animals have shown that specially selected probiotics exert an effect on these mechanisms and can prevent bacterial translocation. Recently, several randomised, double-blind, placebo-controlled trials evaluating prophylactic treatment with enteral probiotics have shown good results. A Dutch multicentre trial, 'Probiotics in pancreatitis trial' (PROPATRIA), is currently underway.

Relationships between air swallowing, intragastric air, belching and gastro-oesophageal reflux.

BACKGROUND: With each swallow a certain amount of air is transported to the stomach. The stomach protects itself against excessive distention by swallowed air through belching (gas reflux). The mechanism of belching (transient lower oesophageal sphincter relaxation) is also one of the mechanisms underlying gastro-oesophageal reflux. AIM: To investigate whether swallowing of air leads to an increase in size of the intragastric air bubble and to gastro-oesophageal reflux. METHODS: Multichannel intraluminal impedance measurement was used to quantify the incidence of swallowing of air in 20 healthy volunteers before and after a meal. Radiography was used to measure the size of the intragastric air bubble. Gastro-oesophageal reflux was assessed by concurrent impedance and pH measurement. RESULTS: The rate of air swallowing was correlated to the size of the intragastric air bubble postprandially and to the rate of gaseous gastro-oesophageal reflux. The number of air swallows and the size of the intragastric air bubble did not correlate with the number of liquid acid and non-acid reflux episodes. CONCLUSIONS: In healthy subjects, air swallowing promotes belching but does not facilitate acid reflux.

Relationship between the mechanism of gastro-oesophageal reflux and oesophageal acid exposure in patients with reflux disease.

This study investigated the relationship between the oesophageal acid exposure time and the underlying manometric motor events in patients with gastro-oesophageal reflux disease (GORD). In 31 patients, 3-hour oesophageal motility and pH were measured after a test meal. Ten patients underwent 24-hour ambulatory manometry and pH recording. In the 3-hour postprandial study, of 367 reflux episodes 79% was associated with a transient lower oesophageal sphincter relaxation (TLOSR), 14% with absent basal lower oesophageal sphincter (LOS) pressure and the remaining 7% with other mechanisms, representing 62, 28 and 10% of the acid exposure time, respectively. Acid reflux duration per motor mechanism was longer for absent basal LOS pressure than for TLOSR (189 +/- 23 s and 41 +/- 5 s, respectively, P < 0.001). In the 24-hour ambulatory study, the contribution of TLOSRs to reflux frequency vs acid exposure time were 65 vs 54% interprandially and 74 vs 53% after the meal. During the night, absence of basal LOS pressure accounted for 36% of reflux events representing 71% of acid exposure time. In conclusion, the duration of oesophageal acid exposure following a TLOSR is shorter than reflux during absent basal LOS pressure. TLOSRs are, the major contributor to oesophageal acid exposure during the day. At night, however, reflux during absent basal LOS pressure is the major contributor to acid exposure.

The effects of the specific 5HT(4) receptor agonist, prucalopride, on colonic motility in healthy volunteers.

BACKGROUND: Prucalopride is a selective and specific 5-hydroxytryptamine(4) receptor agonist that is known to increase stool frequency and to accelerate colonic transit. AIM: To investigate the effect of prucalopride on high-amplitude propagated contractions and segmental pressure waves in healthy volunteers. METHODS: After 1 week of dosing (prucalopride or placebo in a double-blind, randomized, crossover fashion), colonic pressures were recorded in 10 healthy subjects using a solid-state pressure catheter with six sensors spaced 10 cm apart. Subjects kept diary records of their bowel habits (frequency, consistency and straining). High-amplitude propagated contractions were analysed visually, comparing their total numbers and using 10-min time windows. Segmental pressure waves were analysed using computer algorithms, quantifying the incidence, amplitude, duration and area under the curve of all detected peaks. RESULTS: When taking prucalopride, stool frequency increased, consistency decreased and subjects strained less. Prucalopride just failed to increase the total number of high-amplitude propagated contractions (P=0.055). The number of 10-min time windows containing high-amplitude propagated contractions was increased by prucalopride (P=0.019). Prucalopride increased the area under the curve per 24 h (P=0.026). CONCLUSIONS: The 5-hydroxytryptamine(4) receptor agonist prucalopride stimulates high-amplitude propagated contractions and increases segmental contractions, which is likely to be the underlying mechanism of its effect on bowel habits in healthy volunteers.

Automated, quantitative analysis of interdigestive small intestinal myoelectric activity in rats.

Quantitative analysis of myoelectric activity (EMG), to investigate small intestinal motility in rats, is normally based on manual classification into sequences of phase I, phase II and phase III. This classification is partly subjective. We aimed to develop a more objective method for the analysis of the migrating myoelectric complex (MMC). From the EMG, a derived signal is calculated as a measure of activity. Depending on the level of this derived signal, the EMG is classified into 'quiescent phase', 'irregular phase' or 'activity front'. The threshold levels for these phases are automatically calculated from the EMG data. A proposal for subdivision into MMCs is automatically generated. To calculate MMC length, the user must manually reject nonpropagated activity fronts. While developing the method, more than 19 derived signals were tested. These included variants of spike frequency, signal power and spike-burst length. The spike frequency signal was chosen because it gave minimal deviation from manual classification. Using the new automated method, recordings from the jejunum of 15 healthy rats were analysed (6 h each). The calculated phase lengths were consistent with the results of manual analysis. The presented method allows objective analysis of the interdigestive EMG signals of the small intestine.

Elicitation of transient lower oesophageal sphincter relaxations in response to gastric distension and meal ingestion.

The aim of this study was to compare the effect of graded gastric barostat distension and meal-induced fundic relaxation on the elicitation of transient lower oesophageal sphincter relaxation (TLOSR). In 15 healthy subjects, stepwise fundic distension and oesophageal manometry were performed simultaneously. Next, the effect of meal ingestion on proximal stomach volume and lower oesophageal sphincter function was studied. During stepwise barostat distension of the proximal stomach, a significant linear correlation between intragastric pressure (r = 0.91; P < 0.01) and the TLOSR rate during inflation and subsequent deflation (r = 0.96; P < 0.01) was found. A similar relationship was found for volume. In addition, after meal ingestion, the TLOSR rate increased significantly from 1.40 +/- 3 to 5.4 +/- 1.5 h-1 (P < 0.01) and 5.2 +/- 1.7 h-1 (P < 0.01), respectively, during the first and second 30-min postprandially. However, at similar calculated intragastric volumes, barostat distension led to a significantly higher TLOSR rate than the meal. Similarly, distension-induced increase in gastric wall tension, estimated from the measured bag pressure and volume using Laplace's law, was associated with significantly higher TLOSR rates (P < 0.01). In conclusion, the rate of TLOSRs in healthy volunteers is directly related to the degree of proximal gastric distension and pressure-controlled barostat distension is a more potent trigger of TLOSRs than a meal. The latter finding suggests that tension receptor activation is an important stimulus for TLOSRs.

Fully automated analysis of colonic manometry recordings.

The purpose of this study was to develop a computer program for fully automated analysis of all presently known motor patterns in human colonic motility recordings. Colonic pressure recordings obtained from 24 healthy volunteers were used. Algorithms were developed for the detection and numerical analysis of five types of pressure waves: antegrade, retrograde, simultaneous, high-amplitude and isolated pressure waves. Furthermore, periodical motor activity was quantified. Validation was performed by comparison with visual analysis by two experienced observers. Patterns recorded during day- and night-time were compared using multiple-factor analysis of variance with Bonferroni correction. Automated analysis correlated well with visual peak detection (r = 0.98, P <0.01) and detection of antegrade pressure waves (r = 0.98, P <0.01). Most motor patterns showed a diurnal variation. During the night, prevalences of antegrade (938 vs 455; P <0.05), retrograde (112 vs 81; P <0.05), high-amplitude (12.9 vs 1.3; P <0.05), isolated pressure waves (1114 vs 765; P <0.05), and periodic motor activity were decreased (7.33 vs 4.47%; P <0.05). However, when expressed as percentage of absolute numbers of pressure waves, prevalences remained constant. In conclusion, fully automated analysis of all hitherto described colonic motility patterns is feasible. During the night, overall wave prevalences markedly decreased, but the distribution over the various motor patterns was preserved.

Interdigestive small bowel motility and duodenal bacterial overgrowth in experimental acute pancreatitis.

The objective of this study is to investigate the effects of an acute necrotizing pancreatitis (ANP), without biliary obstruction, on the migrating motor complex (MMC), small bowel bacterial overgrowth (SBBO), bacterial translocation (BT) and infection of the pancreas simultaneously. Rats were divided into four groups: mild pancreatitis, control, ANP and sham operated control. Jejunal myoelectrodes were used to measure MMCs. Blood, peritoneal fluid, bile, and abdominal organs were harvested for microbial culturing 72 h after induction of pancreatitis. The splenic portion of the pancreas was taken for histology. During ANP the MMC cycle length was significantly increased from 14.1 +/- 0.2 to 22.4 +/- 1.9 min (P < 0.05). The duodenum of ANP rats was in contrast with the other groups characterized by Enterobacteriacae (> 3 log 10 CFU g-1 in seven of 12 rats, P < 0.05). A positive correlation (r = 0.78, P < 0.01) existed between duodenal Gram-negative and anaerobic flora and the MMC cycle. Correlation between MMC cycle length and BT to the pancreas was positive as well (r = 0.70, P < 0.01). A positive correlation (r = 0.85, P < 0.01) was found between the severity of pancreatitis and duodenal bacterial overgrowth. During ANP without biliary obstruction, the jejunal MMC is disturbed and consequently SBBO occurs. The correlation between the severity of pancreatitis, the disturbance of the MMC and SBBO suggests an important pathophysiological role of the proximal small bowel in the infection of pancreatic necrosis.

Effects of long-term intravenous and intragastric L-arginine intervention on jejunal motility and visceral nitric oxide production in the hyperdynamic compensated endotoxaemic pig.

Alterations in L-arginine availability and nitric oxide (NO) synthesis in the intestinal muscularis may contribute to disturbed small intestinal motility that is observed during endotoxaemia. The aim of this study was to evaluate the effect of L-arginine infusion on visceral NO production and jejunal motility in hyperdynamic compensated endotoxaemic pigs. Fasted and saline-resuscitated pigs were intravenously infused for 24 h with endotoxin (lipopolysaccharide, 50 ng kg(-1) min(-1)) or saline (n = 6). Endotoxaemic pigs received either intravenous L-arginine (n = 6, 5.3 micromol kg(-1) min(-1)) or L-alanine (isocaloric, n = 6). After 24 h, intravenous L-arginine or L-alanine infusion was continued intragastrically for 32-h in an enteral meal. During (0-24 h) and 1 day postendotoxaemia (48-56 h), jejunal motility was recorded by manometry and analysed for migrating motor complex (MMC) characteristics. Visceral NO production was measured at 24 and 48 h by 15N2-arginine-to-15N-citrulline conversion. Visceral NO production was increased during endotoxaemia and was higher in L-arginine than in L-alanine-treated pigs. One day postendotoxaemia, visceral NO synthesis was still increased in L-arginine but not in L-alanine-treated animals. Endotoxaemia shortened the MMC cycle duration and accelerated the MMC propagation velocity. Both were restored by L-arginine. Similar motility disturbances were observed one day postendotoxaemia and were also compensated by L-arginine infusion.

Effects of motilin on human interdigestive gastrointestinal and gallbladder motility, and involvement of 5HT3 receptors.

A plasma motilin peak and a partial gallbladder emptying precede the antral phase III of the migrating motor complex (MMC). To clarify the causal relationship between these factors, we aimed to study the role of motilin in interdigestive gastrointestinal and gallbladder motility simultaneously. In addition, involvement of 5HT3 receptors in the action of motilin was studied. Eight fasting, healthy male volunteers received 13Leu-motilin or 0.9% NaCl i.v. for 30 min, in randomized order on two separate occasions, from 30 min after phase III. Seven of the eight subjects also received the 5HT3 receptor antagonist ondansetron in addition to motilin, on a third occasion. Antroduodenal motility, gallbladder volumes and plasma motilin were measured. The interval between the start of infusion and phase III was 95.0 (57.6-155.7) min for saline, 28.7 (21.0-33.2) min for motilin, and 39.3 (30.7-100.5) min for motilin + ondansetron (P < 0.05). Gallbladder volume decreased by one-third from 10 min after both motilin and motilin + ondansetron infusion (P < 0.05), and returned to baseline with duodenal passage of phase III. In two of the seven subjects phase III was absent after motilin + ondansetron, although gallbladder volume decreased and only refilled during a later spontaneous phase III. We conclude that motilin induces both partial gallbladder emptying and antral phase III. Indeed, although gallbladder emptying clearly precedes antral phase III, ondansetron only prevented phase III in some cases and had no effect on gallbladder emptying. Passage of phase III in the duodenum makes an important contribution to gallbladder refilling.

Differential effects of motilin on interdigestive motility of the human gastric antrum, pylorus, small intestine and gallbladder.

Motilin was infused in this study with the aim of examining refractory characteristics for motilin stimulation of antral phase III and fasting gallbladder emptying. Moreover, interdigestive pyloric and small intestinal motility from duodenum to ileum were studied, as these may be target organs for motilin. Eight fasting, healthy male volunteers received, on separate subsequent days, repeated infusions of 13leucine-motilin (8 pmol (kg min)(-1) for 5 min) or saline at 30 min after phase IIIs in the duodenum. Interdigestive motility of the antrum, pylorus, duodenum, jejunum and ileum was measured for maximum 10 h by using a 21-lumen perfused catheter. Gallbladder motility was measured by ultrasonography. Motilin infusions induced antral phase IIIs, but only after a preceding phase III of duodenal origin. Under this condition, time-interval to phase III at the duodenal recording site was 30 +/- 13 (SEM) min after motilin, compared with 79 +/- 14 min after saline (P < 0.01), and compared with 121 +/- 13 min for motilin infusion following an antral phase III (P < 0.001). Motilin did not affect small intestinal motility or isolated pyloric pressure waves (IPPWs). However, the number of IPPWs was significantly affected by the origin of the preceding phase III, irrespective of whether motilin or saline was infused. Gallbladder volume decreased significantly within 10 min after each motilin infusion. We conclude that this study clearly demonstrates differential regional effects of motilin. Motilin initiates antral phase IIIs, but stimulation is subject to a refractory period which is clearly prolonged after a preceding antral phase III. Motilin induced gallbladder emptying, however, is not subject to a refractory state. Small intestinal phase IIIs as well as pyloric IPPWs are not affected by motilin.

The effects of probiotics on barrier function and mucosal pouch microbiota during maintenance treatment for severe pouchitis in patients with ulcerative colitis.

BACKGROUND: A total of 10-15% of patients with an ileoanal pouch develop severe pouchitis necessitating long-term use of antibiotics or pouch excision. Probiotics reduce the risk of recurrence of pouchitis, but mechanisms behind these effects are not fully understood. AIM: To examine mucosal barrier function in pouchitis, before and after probiotic supplementation and to assess composition of mucosal pouch microbiota. METHODS: Sixteen patients with severe pouchitis underwent endoscopy with biopsies of the pouch on three occasions: during active pouchitis; clinical remission by 4 weeks of antibiotics; after 8 weeks of subsequent probiotic supplementation (Ecologic 825, Winclove, Amsterdam, the Netherlands). Thirteen individuals with a healthy ileoanal pouch were sampled once as controls. Ussing chambers were used to assess transmucosal passage of Escherichia coli K12, permeability to horseradish peroxidase (HRP) and 5¹Cr-EDTA. Composition and diversity of the microbiota was analysed using Human Intestinal Tract Chip. RESULTS: Pouchitis Disease Activity Index (PDAI) was significantly improved after antibiotic and probiotic supplementation. Escherichia coli K12 passage during active pouchitis [3.7 (3.4-8.5); median (IQR)] was significantly higher than in controls [1.7 (1.0-2.4); P < 0.01], did not change after antibiotic treatment [5.0 (3.3-7.1); P = ns], but was significantly reduced after subsequent probiotic supplementation [2.2 (1.7-3.3); P < 0.05]. No significant effects of antibiotics or probiotics were observed on composition of mucosal pouch microbiota; however, E. coli passage correlated with bacterial diversity (r = -0.40; P = 0.018). Microbial groups belonging to Bacteroidetes and Clostridium clusters IX, XI and XIVa were associated with healthy pouches. CONCLUSIONS: Probiotics restored the mucosal barrier to E. coli and HRP in patients with pouchitis, a feasible factor in prevention of recurrence during maintenance treatment. Restored barrier function did not translate into significant changes in mucosal microbiota composition, but bacterial diversity correlated with barrier function.

Electrical tissue impedance spectroscopy: a novel device to measure esophageal mucosal integrity changes during endoscopy.

BACKGROUND: Patients with gastroesophageal reflux disease (GERD) have impaired esophageal mucosal integrity. Measurement of the mucosal integrity is complex and time-consuming. Electrical tissue impedance spectroscopy (ETIS) is a device that measures impedance of tissue in vivo during endoscopy. In this study, we aimed to validate ETIS as a measure of esophageal mucosal integrity. METHODS: Electrical tissue impedance spectroscopy measurements were performed during upper endoscopy in 12 GERD patients and 11 healthy controls after cessation of proton pump inhibition. During endoscopy biopsies of the distal esophagus were obtained for transmission electron microscopy to determine dilation of intercellular spaces (DIS) and for Ussing chamber experiments to determine transepithelial permeability and transepithelial electrical resistance. KEY RESULTS: Extracellular impedance measured in vivo by ETIS was significantly lower in GERD patients compared to controls [mean (SD) 5621 (3299) Ω.m and 8834 (2542) Ω.m, respectively, P < 0.05]. We found a strong inverse relation between extracellular impedance determined by ETIS and DIS (r = -0.76, P < 0.05), and between extracellular resistance in vivo and transepithelial permeability of esophageal biopsies (r = -0.65, P < 0.01). CONCLUSIONS & INFERENCES: Electrical tissue impedance spectroscopy is a new tool that can be used to evaluate esophageal mucosal integrity changes during endoscopy.

CGRP1 receptor activation induces piecemeal release of protease-1 from mouse bone marrow-derived mucosal mast cells.

BACKGROUND: The parasitized or inflamed gastrointestinal mucosa shows an increase in the number of mucosal mast cells (MMC) and the density of extrinsic primary afferent nerve fibers containing the neuropeptide, calcitonin gene-related peptide (CGRP). Currently, the mode of action of CGRP on MMC is unknown. METHODS: The effects of CGRP on mouse bone marrow-derived mucosal mast cells (BMMC) were investigated by measurements of intracellular Ca(2+)[Ca(2+)](i) and release of mMCP-1. KEY RESULTS: Bone marrow-derived mucosal mast cells responded to the application of CGRP with a single transient rise in [Ca(2+)](i). The proportion of responding cells increased concentration-dependently to a maximum of 19 ± 4% at 10(-5)mol L(-1) (mean ±SEM; C48/80 100%; EC(50)10(-8) mol L(-1) ). Preincubation with the CGRP receptor antagonist BIBN4096BS (10(-5) mol L(-1)) completely inhibited BMMC activation by CGRP [range 10(-5) to 10(-11) mol L(-1); analysis of variance (ANOVA) P < 0.001], while preincubation with LaCl(3) to block Ca(2+) entry did not affect the response (P = 0.18). The presence of the CGRP1 receptor on BMMC was confirmed by simultaneous immunofluorescent detection of RAMP1 or CRLR, the two components of the CGRP1 receptor, and mMCP-1. Application of CGRP for 1 h evoked a concentration-dependent release of mMCP-1 (at EC(50) 10% of content) but not of ß-hexosaminidase and alterations in granular density indicative of piecemeal release. CONCLUSIONS & INFERENCES: We demonstrate that BMMC express functional CGRP1 receptors and that their activation causes mobilization of Ca(2+) from intracellular stores and piecemeal release of mMCP-1. These findings support the hypothesis that the CGRP signaling from afferent nerves to MMC in the gastrointestinal wall is receptor-mediated.

Trypsinogen IV, serotonin transporter transcript levels and serotonin content are increased in small intestine of irritable bowel syndrome patients.

Colorectal and small intestinal visceral hypersensitivity has been demonstrated in irritable bowel syndrome (IBS). Serine protease signalling via protease-activated receptor (PAR)-2 promotes hyperalgesia to mechanical distension. Furthermore, serotonergic pathways are involved in gastrointestinal visceral sensitivity. Abnormalities of serine protease and serotonergic signalling components have been identified in IBS colorectal mucosal biopsies. We determined the role of altered mucosal serine protease and serotonergic signalling in small intestine of IBS patients. Duodenal mucosal biopsies of 34 IBS patients (10 constipation-,11 diarrhoea-predominant and 13 alternating) and 20 healthy subjects (HS) were collected. Gene transcripts of PAR-2, trypsinogen IV, TPH-1, SERT (serotonin transport protein) and serotonin (5-HT(3)) subunits were quantified using real-time PCR and 5-HT content was measured by ELISA. Irritable bowel syndrome patients showed 1.5-fold higher trypsinogen IV mRNA level compared to HS (P = 0.016). SERT expression was 1.8-fold higher in IBS compared to HS (P = 0.007). Mucosal 5-HT content was 1.7-fold higher in IBS compared to HS (P = 0.015). The increase was 2.1-fold in IBS-C relative to HS (P = 0.018). Transcript levels of PAR-2, TPH-1 and 5-HT(3) receptor subunits did not differ between IBS and HS. In conclusion enhanced trypsinogen IV expression in IBS may cause increased PAR-2 activation. Increased SERT expression and mucosal 5-HT content in IBS suggest higher 5-HT availability. Both may contribute to small intestinal visceral hypersensitivity in IBS patients.

Antimicrobial activity of a multispecies probiotic (Ecologic 641) against pathogens isolated from infected pancreatic necrosis.

AIMS: Although probiotic prophylaxis has been suggested to prevent small bowel bacterial overgrowth, bacterial translocation and infection of pancreatic necrosis in severe acute pancreatitis, limited data are available on their antimicrobial activity. METHODS AND RESULTS: Using the well-diffusion method, we studied the antimicrobial properties of a multispecies probiotic product (Ecologic 641) against a collection of pathogens cultured from infected pancreatic necrosis. All individual probiotic strains included in the multispecies preparation were able to inhibit the growth of the pathogens to some extent. However, the combination of the individual strains (i.e. the multispecies preparation) was able to inhibit all pathogenic isolates. Probiotic-free supernatants adjusted to pH 7 were not able to inhibit pathogen growth. CONCLUSION: Ecologic 641 is capable of inhibiting growth of a wide variety of pathogens isolated from infected pancreatic necrosis. The antimicrobial properties are to a large extent explained by the production of organic acids. SIGNIFICANCE AND IMPACT OF THE STUDY: Ecologic 641 is currently being used in a Dutch nationwide double-blind, placebo-controlled, randomized multicentre trial in patients with predicted severe acute pancreatitis.

Indomethacin disrupts the protective effect of phosphatidylcholine against bile salt-induced ileal mucosa injury.

BACKGROUND: Indomethacin (Indo) exerts local toxic effects on small intestinal mucosa, possibly in association with hydrophobic bile salts. We investigated the potential toxic effects of Indo on ileal mucosa and the role of phosphatidylcholine (PC). MATERIALS AND METHODS: Transmucosal resistance and Na-fluorescein permeability of ileal mucosa segments from female Wistar rats were determined in Ussing chambers during a 30-min incubation with model systems containing: control-buffer, taurodeoxycholate (TDC), Indo, TDC-Indo, TDC-PC, or TDC-PC-Indo. Decrease of resistance and increase of permeability were considered as parameters for mucosal injury. After incubation in Ussing chambers, the histopathology was examined to quantify the extent of mucosal injury. Also, in CaCo-2 cells, LDH-release was determined as a measure of cytotoxicity, after incubation with various model systems. RESULTS: Decrease of resistance and increase of permeability were highest in systems containing TDC-Indo (P < 0.01). Phosphatidylcholine protected against the cytotoxic effects of TDC in absence of Indo only. Extent of mucosal injury by histological examination was also highest in systems containing TDC-Indo (P = 0.006). Again, PC exhibited protective effects in absence of Indo only. The LDH-release by CaCo2-cells was strongest in TDC-Indo systems (P < 0.001). CONCLUSIONS: Indomethacin disrupts protective effects of PC against bile salt-induced ileal mucosa injury. This finding is relevant for small intestinal injury induced by non-steroidal anti-inflammatory drugs.