Early versus on-demand nasoenteric tube feeding in acute pancreatitis.

BACKGROUND: Early enteral feeding through a nasoenteric feeding tube is often used in patients with severe acute pancreatitis to prevent gut-derived infections, but evidence to support this strategy is limited. We conducted a multicenter, randomized trial comparing early nasoenteric tube feeding with an oral diet at 72 hours after presentation to the emergency department in patients with acute pancreatitis. METHODS: We enrolled patients with acute pancreatitis who were at high risk for complications on the basis of an Acute Physiology and Chronic Health Evaluation II score of 8 or higher (on a scale of 0 to 71, with higher scores indicating more severe disease), an Imrie or modified Glasgow score of 3 or higher (on a scale of 0 to 8, with higher scores indicating more severe disease), or a serum C-reactive protein level of more than 150 mg per liter. Patients were randomly assigned to nasoenteric tube feeding within 24 hours after randomization (early group) or to an oral diet initiated 72 hours after presentation (on-demand group), with tube feeding provided if the oral diet was not tolerated. The primary end point was a composite of major infection (infected pancreatic necrosis, bacteremia, or pneumonia) or death during 6 months of follow-up. RESULTS: A total of 208 patients were enrolled at 19 Dutch hospitals. The primary end point occurred in 30 of 101 patients (30%) in the early group and in 28 of 104 (27%) in the on-demand group (risk ratio, 1.07; 95% confidence interval, 0.79 to 1.44; P=0.76). There were no significant differences between the early group and the on-demand group in the rate of major infection (25% and 26%, respectively; P=0.87) or death (11% and 7%, respectively; P=0.33). In the on-demand group, 72 patients (69%) tolerated an oral diet and did not require tube feeding. CONCLUSIONS: This trial did not show the superiority of early nasoenteric tube feeding, as compared with an oral diet after 72 hours, in reducing the rate of infection or death in patients with acute pancreatitis at high risk for complications. (Funded by the Netherlands Organization for Health Research and Development and others; PYTHON Current Controlled Trials number, ISRCTN18170985.).

SERT and TPH-1 mRNA expression are reduced in irritable bowel syndrome patients regardless of visceral sensitivity state in large intestine.

Colorectal visceral hypersensitivity has been demonstrated in a subset of irritable bowel syndrome (IBS) patients. Serine protease and serotonergic signaling modulate gastrointestinal visceral sensitivity. We evaluated whether altered mucosal serine protease and serotonergic pathway components are related to rectal visceral hypersensitivity in IBS patients. Colorectal mucosal biopsies of 23 IBS patients and 15 controls were collected. Gene transcripts of protease-activated receptor (PAR)-2, trypsinogen IV, tryptophan hydroxylase (TPH)-1, and serotonin reuptake transporter (SERT) were quantified using real-time polymerase chain reaction. Substance P and 5-HT contents were measured by ELISA. The number of enterochromaffin cells, mast cells, and intraepithelial lymphocytes was determined using immunohistochemistry. Rectal visceral sensitivity was determined in IBS patients using barostat programmed for phasic ascending distension. Rectal hypersensitivity (+) and (-) IBS patients showed lower TPH-1 and SERT mRNA levels in the rectum compared with controls (P ≤ 0.05). Rectal hypersensitivity (+) IBS patients (n = 12) showed lower TPH-1 mRNA level in the sigmoid compared with controls (P = 0.015). No significant differences were observed in PAR-2 and trypsinogen IV expression between controls and IBS patients. Rectal substance P content was increased in IBS patients compared with controls (P = 0.045). No significant differences were found in transcript levels, cell counts, and substance P and 5-HT contents between rectal hypersensitivity (+) and (-) IBS patients. In conclusion, regardless of visceral hypersensitivity state, several serotonergic signaling components are altered in IBS patients.

Correlation between protection against sepsis by probiotic therapy and stimulation of a novel bacterial phylotype.

Prophylactic probiotic therapy has shown beneficial effects in an experimental rat model for acute pancreatitis on the health status of the animals. Mechanisms by which probiotic therapy interferes with severity of acute pancreatitis and associated sepsis, however, are poorly understood. The aims of this study were to identify the probiotic-induced changes in the gut microbiota and to correlate these changes to disease outcome. Duodenum and ileum samples were obtained from healthy and diseased rats subjected to pancreatitis for 7 days and prophylactically treated with either a multispecies probiotic mixture or a placebo. Intestinal microbiota was characterized by terminal-restriction fragment length polymorphism (T-RFLP) analyses of PCR-amplified 16S rRNA gene fragments. These analyses showed that during acute pancreatitis the host-specific ileal microbiota was replaced by an "acute pancreatitis-associated microbiota." This replacement was not reversed by administration of the probiotic mixture. An increase, however, was observed in the relative abundance of a novel bacterial phylotype most closely related to Clostridium lituseburense and referred to as commensal rat ileum bacterium (CRIB). Specific primers targeting the CRIB 16S rRNA gene sequence were developed to detect this phylotype by quantitative PCR. An ileal abundance of CRIB 16S rRNA genes of more than 7.5% of the total bacterial 16S rRNA gene pool was correlated with reduced duodenal bacterial overgrowth, reduced bacterial translocation to remote organs, improved pancreas pathology, and reduced proinflammatory cytokine levels in plasma. Our current findings and future studies involving this uncharacterized bacterial phylotype will contribute to unraveling one of the potential mechanisms of probiotic therapy.

Intestinal permeability in irritable bowel syndrome patients: effects of NSAIDs.

Intestinal permeability and the effect of NSAIDs on permeability were investigated in 14 irritable bowel syndrome (IBS) patients and 15 healthy subjects. In the study, 24-h urinary recoveries of orally administered polyethylene glycols (PEGs 400, 1500, and 4000) were not significantly different in healthy subjects and IBS patients before or after NSAID ingestion. Lactulose mannitol ratios in healthy subjects and IBS patients were not significantly different. Only time-dependent monitoring of PEG excretion showed that NSAIDs enhanced intestinal permeability for PEG 4000 in healthy subjects (P = 0.050) and for PEGs 400, 1500, and 4000 in IBS patients (P = 0.012, P = 0.041, and P = 0.012, respectively). These results show that intestinal permeability in IBS patients is not different from that in healthy subjects; NSAIDs compromise intestinal permeability in IBS patients to a greater extent than in healthy subjects, which suggests that IBS is associated with an altered response of the intestinal barrier to noxious agents.

Intestinal barrier dysfunction in a randomized trial of a specific probiotic composition in acute pancreatitis.

OBJECTIVES: To determine the relation between intestinal barrier dysfunction, bacterial translocation, and clinical outcome in patients with predicted severe acute pancreatitis and the influence of probiotics on these processes. SUMMARY OF BACKGROUND DATA: Randomized, placebo-controlled, multicenter trial on probiotic prophylaxis (Ecologic 641) in patients with predicted severe acute pancreatitis (PROPATRIA). METHODS: Excretion of intestinal fatty acid binding protein (IFABP, a parameter for enterocyte damage), recovery of polyethylene glycols (PEGs, a parameter for intestinal permeability), and excretion of nitric oxide (NOx, a parameter for bacterial translocation) were assessed in urine of 141 patients collected 24 to 48 h after start of probiotic or placebo treatment and 7 days thereafter. RESULTS: IFABP concentrations in the first 72 hours were higher in patients who developed bacteremia (P = 0.03), infected necrosis (P = 0.01), and organ failure (P = 0.008). PEG recovery was higher in patients who developed bacteremia (PEG 4000, P = 0.001), organ failure (PEG 4000, P < 0.0001), or died (PEG 4000, P = 0.009). Probiotic prophylaxis was associated with an increase in IFABP (median 362 vs. 199 pg/mL; P = 0.02), most evidently in patients with organ failure (P = 0.001), and did not influence intestinal permeability. Overall, probiotics decreased NOx (P = 0.05) but, in patients with organ failure, increased NOx (P = 0.001). CONCLUSIONS: Bacteremia, infected necrosis, organ failure, and mortality were all associated with intestinal barrier dysfunction early in the course of acute pancreatitis. Overall, prophylaxis with this specific combination of probiotic strains reduced bacterial translocation, but was associated with increased bacterial translocation and enterocyte damage in patients with organ failure.

The role of microbiota and probiotics in stress-induced gastro-intestinal damage.

Stress has a major impact on gut physiology and may affect the clinical course of gastro-intestinal diseases. In this review, we focus on the interaction between commensal gut microbiota and intestinal mucosa during stress and discuss the possibilities to counteract the deleterious effects of stress with probiotics. Normally, commensal microbes and their hosts benefit from a symbiotic relationship. Stress does, however, reduce the number of Lactobacilli, while on the contrary, an increased growth, epithelial adherence and mucosal uptake of gram-negative pathogens, e.g. E. coli and Pseudomonas, are seen. Moreover, intestinal bacteria have the ability to sense a stressed host and up-regulate their virulence factors when opportunity knocks. Probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host", and mainly represented by Lactic Acid Bacteria. Probiotics can counteract stress-induced changes in intestinal barrier function, visceral sensitivity and gut motility. These effects are strain specific and mediated by direct bacterial-host cell interaction and/or via soluble factors. Mechanisms of action include competition with pathogens for essential nutrients, induction of epithelial heat-shock proteins, restoring of tight junction protein structure, up-regulation of mucin genes, secretion of defensins, and regulation of the NFkappaB signalling pathway. In addition, the reduction of intestinal pain perception was shown to be mediated via cannabinoid receptors. Based on the studies reviewed here there is clearly a rationale for probiotic treatment in patients with stress-related intestinal disorders. We are however far from being able to choose the precise combination of strains or bacterial components for each clinical setting.

Critical evaluation of diagnosing bacterial overgrowth in the proximal small intestine.

BACKGROUND: Clinical small bowel bacterial overgrowth (SBBO) syndrome can be objectified by bacterial overgrowth tests. As direct culture of jejunal aspirates has disadvantages, noninvasive tests such as breath tests (BTs) are used. Major drawback of lactulose BT might be rapid lactulose transit to the colon. We evaluated diagnosing bacterial overgrowth using experimental and standard BT, and culture and molecular-based methods. STUDY: Bacterial overgrowth was analyzed in 11 controls and 15 SBBO predisposed subjects. During experimental breath testing, an occlusive balloon limited lactulose to the small intestine. Jejunal fluid was analyzed using culture and molecular-based methods. Bacterial overgrowth was diagnosed on the basis of 20 ppm hydrogen or methane increase above baseline within 90 minutes or more than 10 CFU/mL excluding lactobacilli and streptococci and furthermore using all published definitions. RESULTS: Experimental and standard BT showed no changes in timing of hydrogen excretion between controls and SBBO subjects. Using standard BT, 3/11 controls and 8/15 SBBO subjects were bacterial overgrowth positive. Total counts showed no significant differences between controls and SBBO subjects using culture and molecular-based methods. Bacterial overgrowth was diagnosed in 0/9 controls and 4/12 SBBO subjects using culture-based methods. Other definitions used in literature revealed no significant differences between controls and SBBO subjects. CONCLUSIONS: In a small group of subjects, the experimental BT did not improve the ability of lactulose BT to diagnose bacterial overgrowth. Culturing showed less bacterial overgrowth in controls compared with BT. Remarkably, current diagnostic criteria do not seem to be accurate in discriminating between SBBO subjects and controls.

Modification of intestinal flora with multispecies probiotics reduces bacterial translocation and improves clinical course in a rat model of acute pancreatitis.

BACKGROUND: Infection of pancreatic necrosis by gut bacteria is a major cause of morbidity and mortality in patients with severe acute pancreatitis. Use of prophylactic antibiotics remains controversial. The aim of this experiment was assess if modification of intestinal flora with specifically designed multispecies probiotics reduces bacterial translocation or improves outcome in a rat model of acute pancreatitis. METHODS: Male Sprague-Dawley rats were allocated into 3 groups: (1) controls (sham-operated, no treatment), (2) pancreatitis and placebo, and (3) pancreatitis and probiotics. Acute pancreatitis was induced by intraductal glycodeoxycholate and intravenous cerulein infusion. Daily probiotics or placebo was administered intragastrically from 5 days prior until 7 days after induction of pancreatitis. Tissue and fluid samples were collected for microbiologic and quantitative real-time PCR analysis of bacterial translocation. RESULTS: Probiotics reduced duodenal bacterial overgrowth of potential pathogens (Log(10) colony-forming units [CFU]/g 5.0 +/- 0.7 [placebo] vs 3.5 +/- 0.3 CFU/g [probiotics], P < .05), resulting in reduced bacterial translocation to extraintestinal sites, including the pancreas (5.38 +/- 1.0 CFU/g [placebo] vs 3.1 +/- 0.5 CFU/g [probiotics], P < .05). Accordingly, health scores were better and late phase mortality was reduced: 27% (4/15, placebo) versus 0% (0/13, probiotics), respectively, P < .05. CONCLUSIONS: This experiment supports the hypothesis that modification of intestinal flora with multispecies probiotics results in reduced bacterial translocation, morbidity, and mortality in the course of experimental acute pancreatitis.

Design of a multispecies probiotic mixture to prevent infectious complications in critically ill patients.

BACKGROUND & AIMS: Although the potential for probiotics is investigated in an increasing variety of diseases, there is little or no consensus regarding the desired probiotic properties for a particular disease in question, nor about the final design of the probiotic. Specific strain selection procedures were undertaken to design a disease-specific multispecies probiotic. METHODS: From a strain collection of 69 different lactic acid bacteria a primary selection was made of 14 strains belonging to different species showing superior survival in a simulated gastrointestinal environment. Functional tests like antimicrobial activity against a range of clinical isolates and cytokine inducing capacity in cultured human peripheral blood mononuclear cells were used to further identify potential strains. RESULTS: Specific strains inhibited growth of clinical isolates whereas others superiorly induced the anti-inflammatory cytokine IL-10. Based on functional tests and general criteria regarding probiotic design and safety, a selection of the following six strains was made (Ecologic 641); Bifidobacterium bifidum, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus salivarius and Lactococcus lactis. Combination of these strains resulted in a wider antimicrobial spectrum, superior induction of IL-10 and silencing of pro-inflammatory cytokines as compared to the individual components. CONCLUSIONS: Application of strict criteria during the design of a disease-specific probiotic prior to implementation in clinical trials may provide a rational basis for use of probiotics.

Variability factors in the expression of stress-induced behavioural sensitisation.

Altered behavioural and physiological responsivity following a short session of foot shocks in the rat has proven to be a stable and clinically relevant model of stress-induced sensitisation. However, a number of key factors influencing effect size or direction have not previously been reported. Rats underwent a single, 15-min session of foot shocks and were exposed to a variety of novel stressful challenges 1 or 2 weeks later. Sensitised behavioural responses (increased immobility) in preshocked rats remained present over 3 days of repeated exposure to noise stress. In mild novel challenges (open field, empty cage), behavioural sensitisation and defecation was most clearly expressed at the beginning of the dark phase (evening). Higher-arousal challenges (prod, noise) caused increased behavioural inhibition in preshocked rats at all three time points (morning, afternoon, evening). Female preshocked rats showed a different pattern of behavioural and defecation sensitisation than preshocked males. The robustness of the model makes it suitable for further investigations into the mechanisms and vulnerability factors involved in the long-term consequences of stress.

Duodenal motility during a run-bike-run protocol: the effect of a sports drink.

OBJECTIVE: To examine the effect of a sports drink during strenuous exercise on duodenal motility and gastrointestinal symptoms. METHODS: In a cross-over design, seven male triathletes performed two 170-min run-bike-run tests at about 70% peak oxygen uptake (O(2peak)), with either a 7% carbohydrate (CHO) sports drink or tap water. Antroduodenal motility (phase III of the migrating motor complex; MMC) was measured with an ambulant manometry system. The effect of the two exercise trials on the first appearance of the MMC was assessed in the postprandial period. RESULTS: Exercise heart rate, percentage O(2peak) and loss of body mass did not differ significantly between the two trials. After the start of the exercise, the expected time before the first phase III occurrence, based on the actual energy intake of the last meal in the morning before exercise (1048 +/- 294 kcal), a fixed gastric emptying rate and a lag phase for solid food, was 183 +/- 113 min (mean +/- standard deviation [SD]). The real time period between the start of the exercise with CHO and the first phase III was 63 +/- 61 min, which was significantly shorter than that observed with tap water (152 +/- 59 min). Both real time periods were shorter than the expected time period of 183 +/- 113 min (P < 0.05). During exercise, the number of subjects with a phase III was higher with CHO than with tap water (n =6 v. n =1; P < 0.05). Also, the median number of phases III per hour with CHO was higher than with tap water (0.4 v. 0.0; P < 0.05). During cycling, significantly more phases III per hour (0.9) were measured than during running (0.2). All subjects reported one or more gastrointestinal symptoms during exercise, however, without a clear association with the mode of exercise or supplementation. CONCLUSIONS: Prolonged exercise results in gastrointestinal symptoms and a significant interruption of postprandial motility. Only the latter phenomenon depends on the mode of exercise and supplementation.

Probiotic prophylaxis in patients with predicted severe acute pancreatitis (PROPATRIA): design and rationale of a double-blind, placebo-controlled randomised multicenter trial [ISRCTN38327949].

BACKGROUND: Infectious complications are the major cause of death in acute pancreatitis. Small bowel bacterial overgrowth and subsequent bacterial translocation are held responsible for the vast majority of these infections. Goal of this study is to determine whether selected probiotics are capable of preventing infectious complications without the disadvantages of antibiotic prophylaxis; antibiotic resistance and fungal overgrowth. METHODS/DESIGN: PROPATRIA is a double-blind, placebo-controlled randomised multicenter trial in which 200 patients will be randomly allocated to a multispecies probiotic preparation (Ecologic 641) or placebo. The study is performed in all 8 Dutch University Hospitals and 7 non-University hospitals. The study-product is administered twice daily through a nasojejunal tube for 28 days or until discharge. Patients eligible for randomisation are adult patients with a first onset of predicted severe acute pancreatitis: Imrie criteria 3 or more, CRP 150 mg/L or more, APACHE II score 8 or more. Exclusion criteria are post-ERCP pancreatitis, malignancy, infection/sepsis caused by a second disease, intra-operative diagnosis of pancreatitis and use of probiotics during the study. Administration of the study product is started within 72 hours after onset of abdominal pain. The primary endpoint is the total number of infectious complications. Secondary endpoints are mortality, necrosectomy, antibiotic resistance, hospital stay and adverse events. To demonstrate that probiotic prophylaxis reduces the proportion of patients with infectious complications from 50% to 30%, with alpha 0,05 and power 80%, a total sample size of 200 patients was calculated. CONCLUSION: The PROPATRIA study is aimed to show a reduction in infectious complications due to early enteral use of multispecies probiotics in severe acute pancreatitis.

Impact of global Fxr deficiency on experimental acute pancreatitis and genetic variation in the FXR locus in human acute pancreatitis.

BACKGROUND: Infectious complications often occur in acute pancreatitis, related to impaired intestinal barrier function, with prolonged disease course and even mortality as a result. The bile salt nuclear receptor farnesoid X receptor (FXR), which is expressed in the ileum, liver and other organs including the pancreas, exhibits anti-inflammatory effects by inhibiting NF-κB activation and is implicated in maintaining intestinal barrier integrity and preventing bacterial overgrowth and translocation. Here we explore, with the aid of complementary animal and human experiments, the potential role of FXR in acute pancreatitis. METHODS: Experimental acute pancreatitis was induced using the CCK-analogue cerulein in wild-type and Fxr-/- mice. Severity of acute pancreatitis was assessed using histology and a semi-quantitative scoring system. Ileal permeability was analyzed in vitro by Ussing chambers and an in vivo permeability assay. Gene expression of Fxr and Fxr target genes was studied by quantitative RT-PCR. Serum FGF19 levels were determined by ELISA in acute pancreatitis patients and healthy volunteers. A genetic association study in 387 acute pancreatitis patients and 853 controls was performed using 9 tagging single nucleotide polymorphisms (SNPs) covering the complete FXR gene and two additional functional SNPs. RESULTS: In wild-type mice with acute pancreatitis, ileal transepithelial resistance was reduced and ileal mRNA expression of Fxr target genes Fgf15, SHP, and IBABP was decreased. Nevertheless, Fxr-/- mice did not exhibit a more severe acute pancreatitis than wild-type mice. In patients with acute pancreatitis, FGF19 levels were lower than in controls. However, there were no associations of FXR SNPs or haplotypes with susceptibility to acute pancreatitis, or its course, outcome or etiology. CONCLUSION: We found no evidence for a major role of FXR in acute human or murine pancreatitis. The observed altered Fxr activity during the course of disease may be a secondary phenomenon.

Association analysis of genetic variants in the myosin IXB gene in acute pancreatitis.

INTRODUCTION: Impairment of the mucosal barrier plays an important role in the pathophysiology of acute pancreatitis. The myosin IXB (MYO9B) gene and the two tight-junction adaptor genes, PARD3 and MAGI2, have been linked to gastrointestinal permeability. Common variants of these genes are associated with celiac disease and inflammatory bowel disease, two other conditions in which intestinal permeability plays a role. We investigated genetic variation in MYO9B, PARD3 and MAGI2 for association with acute pancreatitis. METHODS: Five single nucleotide polymorphisms (SNPs) in MYO9B, two SNPs in PARD3, and three SNPs in MAGI2 were studied in a Dutch cohort of 387 patients with acute pancreatitis and over 800 controls, and in a German cohort of 235 patients and 250 controls. RESULTS: Association to MYO9B and PARD3 was observed in the Dutch cohort, but only one SNP in MYO9B and one in MAGI2 showed association in the German cohort (p < 0.05). Joint analysis of the combined cohorts showed that, after correcting for multiple testing, only two SNPs in MYO9B remained associated (rs7259292, p = 0.0031, odds ratio (OR) 1.94, 95% confidence interval (95% CI) 1.35-2.78; rs1545620, p = 0.0006, OR 1.33, 95% CI 1.16-1.53). SNP rs1545620 is a non-synonymous SNP previously suspected to impact on ulcerative colitis. None of the SNPs showed association to disease severity or etiology. CONCLUSION: Variants in MYO9B may be involved in acute pancreatitis, but we found no evidence for involvement of PARD3 or MAGI2.

Molecular analysis of faecal and duodenal samples reveals significantly higher prevalence and numbers of Pseudomonas aeruginosa in irritable bowel syndrome.

Intestinal microbiota may play a role in the pathophysiology of irritable bowel syndrome (IBS). In this case-control study, mucosa-associated small intestinal and faecal microbiota of IBS patients and healthy subjects were analysed using molecular-based methods. Duodenal mucosal brush and faecal samples were collected from 37 IBS patients and 20 healthy subjects. The bacterial 16S rRNA gene was amplified and analysed using PCR denaturing gradient gel electrophoresis (DGGE). Pooled average DGGE profiles of all IBS patients and all healthy subjects from both sampling sites were generated and fingerprints of both groups were compared. The DGGE band fragments which were confined to one group were further characterized by sequence analysis. Quantitative real-time PCR (q-PCR) was used to quantify the disease-associated microbiota. Averaged DGGE profiles of both groups were identical for 78.2 % in the small intestinal samples and for 86.25 % in the faecal samples. Cloning and sequencing of the specific bands isolated from small intestinal and faecal DGGE patterns of IBS patients showed that 45.8 % of the clones belonged to the genus Pseudomonas, of which Pseudomonas aeruginosa was the predominant species. q-PCR analysis revealed higher levels (P<0.001) of P. aeruginosa in the small intestine of IBS patients (8.3 %±0.950) than in the small intestine of healthy subjects (0.1 %±0.069). P. aeruginosa was also significantly (P<0.001) more abundant (2.34 %±0.31) in faeces of IBS patients than in faeces of healthy subjects (0.003 %±0.0027). This study shows that P. aeruginosa is detected more frequently and at higher levels in IBS patients than in healthy subjects, suggesting its potential role in the pathophysiology of IBS.

Pancreatitis, very early compared with normal start of enteral feeding (PYTHON trial): design and rationale of a randomised controlled multicenter trial.

BACKGROUND: In predicted severe acute pancreatitis, infections have a negative effect on clinical outcome. A start of enteral nutrition (EN) within 24 hours of onset may reduce the number of infections as compared to the current practice of starting an oral diet and EN if necessary at 3-4 days after admission. METHODS/DESIGN: The PYTHON trial is a randomised controlled, parallel-group, superiority multicenter trial. Patients with predicted severe acute pancreatitis (Imrie-score ≥ 3 or APACHE-II score ≥ 8 or CRP > 150 mg/L) will be randomised to EN within 24 hours or an oral diet and EN if necessary, after 72 hours after hospital admission.During a 3-year period, 208 patients will be enrolled from 20 hospitals of the Dutch Pancreatitis Study Group. The primary endpoint is a composite of mortality or infections (bacteraemia, infected pancreatic or peripancreatic necrosis, pneumonia) during hospital stay or within 6 months following randomisation. Secondary endpoints include other major morbidity (e.g. new onset organ failure, need for intervention), intolerance of enteral feeding and total costs from a societal perspective. DISCUSSION: The PYTHON trial is designed to show that a very early (< 24 h) start of EN reduces the combined endpoint of mortality or infections as compared to the current practice of an oral diet and EN if necessary at around 72 hours after admission for predicted severe acute pancreatitis. TRIAL REGISTRATION: ISRCTN: ISRCTN18170985.

Safety assessment of probiotics for human use.

The safety of probiotics is tied to their intended use, which includes consideration of potential vulnerability of the consumer or patient, dose and duration of consumption, and both the manner and frequency of administration. Unique to probiotics is that they are alive when administered, and unlike other food or drug ingredients, possess the potential for infectivity or in situ toxin production. Since numerous types of microbes are used as probiotics, safety is also intricately tied to the nature of the specific microbe being used. The presence of transferable antibiotic resistance genes, which comprises a theoretical risk of transfer to a less innocuous member of the gut microbial community, must also be considered. Genetic stability of the probiotic over time, deleterious metabolic activities, and the potential for pathogenicity or toxicogenicity must be assessed depending on the characteristics of the genus and species of the microbe being used. Immunological effects must be considered, especially in certain vulnerable populations, including infants with undeveloped immune function. A few reports about negative probiotic effects have surfaced, the significance of which would be better understood with more complete understanding of the mechanisms of probiotic interaction with the host and colonizing microbes. Use of readily available and low cost genomic sequencing technologies to assure the absence of genes of concern is advisable for candidate probiotic strains. The field of probiotic safety is characterized by the scarcity of studies specifically designed to assess safety contrasted with the long history of safe use of many of these microbes in foods.

Lower Bifidobacteria counts in both duodenal mucosa-associated and fecal microbiota in irritable bowel syndrome patients.

AIM: To determine the composition of both fecal and duodenal mucosa-associated microbiota in irritable bowel syndrome (IBS) patients and healthy subjects using molecular-based techniques. METHODS: Fecal and duodenal mucosa brush samples were obtained from 41 IBS patients and 26 healthy subjects. Fecal samples were analyzed for the composition of the total microbiota using fluorescent in situ hybridization (FISH) and both fecal and duodenal brush samples were analyzed for the composition of bifidobacteria using real-time polymerase chain reaction. RESULTS: The FISH analysis of fecal samples revealed a 2-fold decrease in the level of bifidobacteria (4.2 +/- 1.3 vs 8.3 +/- 1.9, P < 0.01) in IBS patients compared to healthy subjects, whereas no major differences in other bacterial groups were observed. At the species level, Bifidobacterium catenulatum levels were significantly lower (6 +/- 0.6 vs 19 +/- 2.5, P < 0.001) in the IBS patients in both fecal and duodenal brush samples than in healthy subjects. CONCLUSION: Decreased bifidobacteria levels in both fecal and duodenal brush samples of IBS patients compared to healthy subjects indicate a role for microbiotic composition in IBS pathophysiology.

Probiotics prevent intestinal barrier dysfunction in acute pancreatitis in rats via induction of ileal mucosal glutathione biosynthesis.

BACKGROUND: During acute pancreatitis (AP), oxidative stress contributes to intestinal barrier failure. We studied actions of multispecies probiotics on barrier dysfunction and oxidative stress in experimental AP. METHODOLOGY/PRINCIPAL FINDINGS: Fifty-three male Spraque-Dawley rats were randomly allocated into five groups: 1) controls, non-operated, 2) sham-operated, 3) AP, 4) AP and probiotics and 5) AP and placebo. AP was induced by intraductal glycodeoxycholate infusion and intravenous cerulein (6 h). Daily probiotics or placebo were administered intragastrically, starting five days prior to AP. After cerulein infusion, ileal mucosa was collected for measurements of E. coli K12 and (51)Cr-EDTA passage in Ussing chambers. Tight junction proteins were investigated by confocal immunofluorescence imaging. Ileal mucosal apoptosis, lipid peroxidation, and glutathione levels were determined and glutamate-cysteine-ligase activity and expression were quantified. AP-induced barrier dysfunction was characterized by epithelial cell apoptosis and alterations of tight junction proteins (i.e. disruption of occludin and claudin-1 and up-regulation of claudin-2) and correlated with lipid peroxidation (r>0.8). Probiotic pre-treatment diminished the AP-induced increase in E. coli passage (probiotics 57.4+/-33.5 vs. placebo 223.7+/-93.7 a.u.; P<0.001), (51)Cr-EDTA flux (16.7+/-10.1 vs. 32.1+/-10.0 cm/s10(-6); P<0.005), apoptosis, lipid peroxidation (0.42+/-0.13 vs. 1.62+/-0.53 pmol MDA/mg protein; P<0.001), and prevented tight junction protein disruption. AP-induced decline in glutathione was not only prevented (14.33+/-1.47 vs. 8.82+/-1.30 nmol/mg protein, P<0.001), but probiotics even increased mucosal glutathione compared with sham rats (14.33+/-1.47 vs. 10.70+/-1.74 nmol/mg protein, P<0.001). Glutamate-cysteine-ligase activity, which is rate-limiting in glutathione biosynthesis, was enhanced in probiotic pre-treated animals (probiotics 2.88+/-1.21 vs. placebo 1.94+/-0.55 nmol/min/mg protein; P<0.05) coinciding with an increase in mRNA expression of glutamate-cysteine-ligase catalytic (GCLc) and modifier (GCLm) subunits. CONCLUSIONS: Probiotic pre-treatment diminished AP-induced intestinal barrier dysfunction and prevented oxidative stress via mechanisms mainly involving mucosal glutathione biosynthesis.

Pretreatment but not treatment with probiotics abolishes mouse intestinal barrier dysfunction in acute pancreatitis.

BACKGROUND: Intestinal barrier failure during acute pancreatitis (AP) is associated with translocation of luminal bacteria, resulting in infectious complications. We examined the effects of multispecies probiotics on the intestinal barrier impairment in a murine model of AP. METHODS: Mice were injected with cerulein to induce AP and were sacrificed 11 (early AP) or 72 hours (late AP) after start of induction. AP and associated systemic effects were confirmed by histology of pancreas and lung. Animals received daily probiotics starting 2 days prior to AP induction (pretreatment) or at the moment of AP induction (treatment). Mucosal barrier function of the distal ileum was assessed in Ussing chambers by measurement of the epithelial electrical resistance and the permeability to Na-fluorescein. RESULTS: Histological analysis revealed pancreatic injury in both phases of AP, and lung damage in the early phase. Epithelial resistance of the ileum was reduced and permeability increased in both phases of AP, indicating impairment of the intestinal barrier. Pretreatment had no effect on resistance or permeability in the early phase of AP. In the late phase of AP, pretreatment but not treatment abolished the AP induced resistance decrease and permeability increase. Administration of probiotics as such (ie, without induction of AP) had no effect on intestinal barrier function. CONCLUSION: Pretreatment with multispecies probiotics for 2 days abolishes intestinal barrier dysfunction in the late phase of AP, while treatment does not. The effectiveness of probiotics in this model depends on the timing of administration. Clinical trials with probiotics should seek conditions where treatment can be started prior to onset of disease or elective surgical intervention.