Gut macromolecular permeability in pancreatitis correlates with severity of disease in rats

Very early and early nutrition in children with pancreatitis-A randomised trial

OBJECTIVES

The aim of our study was to assess the impact of the very early introduction of refeeding on the course of acute pancreatitis (AP) in children. Additionally, we evaluated the effect of nutrition on inflammatory markers, including cytokines.

METHODS

This prospective randomised study was conducted in three university hospitals in Poland. Patients, aged 1-18 years with AP, were randomised into two groups: A-refeeding within 24 h of hospital admission (very early), and B-refeeding at least 24 h after admission (early nutrition). The severity of AP was assessed after 48 h. The serum concentrations of four cytokines (tumour necrosis factor α [TNFα], interleukin-1β [IL-1β], interleukin-6 [IL-6] and interleukin-8 [IL-8]) and C-reactive protein, as well as the activity of amylase, lipase and aminotransferases, were measured during the first 3 days of hospitalisation.

RESULTS

A total of 94 children were recruited to participate in the study. The statistical analysis included 75 patients with mild pancreatitis: 42-group A and 33-group B. The two groups did not differ in the length of hospitalisation (p = 0.22), AP symptoms or results of laboratory tests. Analysis of cytokine levels was conducted for 64 children: 38-group A and 26-group B. We did not find a difference in concentrations of the measured cytokines, except for IL-1β on the third day of hospitalisation (p = 0.01).

CONCLUSIONS

The time of initiation of oral nutrition within 24 h (very early) or after 24 h (early) from the beginning of hospitalisation had no impact on the length of hospitalisation, concentrations of TNF-α, IL-1β, IL-6 and IL-8, activity of amylase and lipase or occurrence of symptoms in children with mild AP.

Exploring the gut microbiota's crucial role in acute pancreatitis and the novel therapeutic potential of derived extracellular vesicles

During acute pancreatitis, intestinal permeability increases due to intestinal motility dysfunction, microcirculatory disorders, and ischemia-reperfusion injury, and disturbances in the intestinal flora make bacterial translocation easier, which consequently leads to local or systemic complications such as pancreatic and peripancreatic necrotic infections, acute lung injury, systemic inflammatory response syndrome, and multiple organ dysfunction syndrome. Therefore, adjusting intestinal ecosystem balance may be a promising approach to control local and systemic complications of acute pancreatitis. In this paper, we reviewed the causes and manifestations of intestinal flora disorders during acute pancreatitis and their complications, focused on the reduction of acute pancreatitis and its complications by adjusting the intestinal microbial balance, and innovatively proposed the treatment of acute pancreatitis and its complications by gut microbiota-derived extracellular vesicles.

Blood-brain barrier dysfunction in L-ornithine induced acute pancreatitis in rats and the direct effect of L-ornithine on cultured brain endothelial cells

BACKGROUND

In severe acute pancreatitis (AP) the CNS is affected manifesting in neurological symptoms. Earlier research from our laboratory showed blood-brain barrier (BBB) permeability elevation in a taurocholate-induced AP model. Here we aimed to further explore BBB changes in AP using a different, non-invasive in vivo model induced by L-ornithine. Our goal was also to identify whether L-ornithine, a cationic amino acid, has a direct effect on brain endothelial cells in vitro contributing to the observed BBB changes.

METHODS

AP was induced in rats by the intraperitoneal administration of L-ornithine-HCl. Vessel permeability and the gene expression of the primary transporter of L-ornithine, cationic amino acid transporter-1 (Cat-1) in the brain cortex, pancreas, liver and lung were determined. Ultrastructural changes were followed by transmission electron microscopy. The direct effect of L-ornithine was tested on primary rat brain endothelial cells and a triple co-culture model of the BBB. Viability and barrier integrity, including permeability and TEER, nitrogen monoxide (NO) and reactive oxygen species (ROS) production and NF-κB translocation were measured. Fluorescent staining for claudin-5, occludin, ZO-1, β-catenin, cell adhesion molecules Icam-1 and Vcam-1 and mitochondria was performed. Cell surface charge was measured by laser Doppler velocimetry.

RESULTS

In the L-ornithine-induced AP model vessel permeability for fluorescein and Cat-1 expression levels were elevated in the brain cortex and pancreas. On the ultrastructural level surface glycocalyx and mitochondrial damage, tight junction and basal membrane alterations, and glial edema were observed. L-ornithine decreased cell impedance and elevated the BBB model permeability in vitro. Discontinuity in the surface glycocalyx labeling and immunostaining of junctional proteins, cytoplasmic redistribution of ZO-1 and β-catenin, and elevation of Vcam-1 expression were measured. ROS production was increased and mitochondrial network was damaged without NF-κB, NO production or mitochondrial membrane potential alterations. Similar ultrastructural changes were seen in L-ornithine treated brain endothelial cells as in vivo. The basal negative zeta potential of brain endothelial cells became more positive after L-ornithine treatment.

CONCLUSION

We demonstrated BBB damage in the L-ornithine-induced rat AP model suggesting a general, AP model independent effect. L-ornithine induced oxidative stress, decreased barrier integrity and altered BBB morphology in a culture BBB model. These data suggest a direct effect of the cationic L-ornithine on brain endothelium. Endothelial surface glycocalyx injury was revealed both in vivo and in vitro, as an additional novel component of the BBB-related pathological changes in AP.

Polyphosphate, Derived from Lactobacillus brevis, Modulates the Intestinal Microbiome and Attenuates Acute Pancreatitis

BACKGROUND

We previously showed that Lactobacillus brevis-derived polyphosphate (poly P) exerts a curative effect on intestinal inflammation. However, whether or not poly P improves the inflammation and injury of distant organs remains unclear.

AIMS

We aimed to investigate the change in the intestinal microbiome and to evaluate the protective effect of poly P on injuries in a cerulein-induced acute pancreatitis (AP) mouse.

METHODS

Poly P was orally administered to BALB/C mice every day for 24 days, and then mice were intraperitoneally injected with cerulein. Before cerulein injection, stool samples were collected and analyzed by 16S rRNA gene sequencing. Mice were sacrificed at 24 h after the last cerulein injection; subsequently, the serum, pancreas, and colon were collected.

RESULTS

The microbial profile differed markedly between poly P and control group. Notably, the levels of beneficial bacteria, including Alistipes and Candidatus_Saccharimonas, were significantly increased, while those of the virulent bacteria Desulfovibrio were decreased in the poly P group. The elevations of the serum amylase and lipase levels by cerulein treatment were suppressed by the pre-administration of poly P for 24 days, but not for 7 days. The numbers of cells MPO-positive by immunohistology were decreased and the levels of MCP-1 significantly reduced in the AP + Poly P group. An immunofluorescence analysis showed that the ZO-1 and occludin in the colon was strongly augmented in the epithelial cell membrane layer in the AP + Poly P group.

CONCLUSIONS

Poly P attenuates AP through both modification of the intestinal microbiome and enhancement of the intestinal barrier integrity.

Escin Sodium Improves the Prognosis of Acute Pancreatitis via Promoting Cell Apoptosis by Suppression of the ERK/STAT3 Signaling Pathway

Acute pancreatitis (AP), an inflammatory disorder of the pancreas, can cause systemic inflammatory responses. Escin Sodium (ES), a natural mixture of triterpene saponins extracted from the dry ripe fruit of Fructus Aesculi or horse chestnut crude, has been demonstrated to have antiedematous, anti-inflammatory, and antiexudative effects. We here aim to investigate the effects of ES pretreatment on AP in vivo and in vitro and explore its potential molecular mechanism. In the present study, we demonstrated that ES pretreatment could apparently decrease amylase and lipase, downregulate inflammatory cytokines, and attenuate pancreatic damage. Additionally, the increased expression of apoptotic-related proteins and the results of flow cytometry demonstrated the effects of ES on promoting apoptosis in acinar cells. Moreover, ES could enhance mitochondrial membrane potential (MMP, ΔΨm) and reactive oxygen species (ROS) level and reduce intracellular calcium concentration, which are closely related to mitochondrial-mediated death. The effect of ES pretreatment on acinar cell apoptosis was furtherly confirmed by the regulatory pathway of the ERK/STAT3 axis. These results suggest that ES attenuates the severity of AP by enhancing cell apoptosis via suppressing the ERK/STAT3 signaling pathway. These findings provide evidence for ES which is treated as a novel and potent therapeutic for the treatment of AP.

Western-type diet influences mortality from necrotising pancreatitis and demonstrates a central role for butyrate

OBJECTIVE

The gut microbiota are the main source of infections in necrotising pancreatitis. We investigated the effect of disruption of the intestinal microbiota by a Western-type diet on mortality and bacterial dissemination in necrotising pancreatitis and its reversal by butyrate supplementation.

DESIGN

C57BL/6 mice were fed either standard chow or a Western-type diet for 4 weeks and were then subjected to taurocholate-induced necrotising pancreatitis. Blood and pancreas were collected for bacteriology and immune analysis. The cecum microbiota composition of mice was analysed using 16S rRNA gene amplicon sequencing and cecal content metabolites were analysed by targeted (ie, butyrate) and untargeted metabolomics. Prevention of necrotising pancreatitis in this model was compared between faecal microbiota transplantation (FMT) from healthy mice, antibiotic decontamination against Gram-negative bacteria and oral or systemic butyrate administration. Additionally, the faecal microbiota of patients with pancreatitis and healthy subjects were analysed.

RESULTS

Mortality, systemic inflammation and bacterial dissemination were increased in mice fed Western diet and their gut microbiota were characterised by a loss of diversity, a bloom of Escherichia coli and an altered metabolic profile with butyrate depletion. While antibiotic decontamination decreased mortality, Gram-positive dissemination was increased. Both oral and systemic butyrate supplementation decreased mortality, bacterial dissemination, and reversed the microbiota alterations. Paradoxically, mortality and bacterial dissemination were increased with FMT administration. Finally, patients with acute pancreatitis demonstrated an increase in Proteobacteria and a decrease of butyrate producers compared with healthy subjects.

CONCLUSION

Butyrate depletion and its repletion appear to play a central role in disease progression towards necrotising pancreatitis.

Effects of Bacterial Translocation and Autophagy on Acute Lung Injury Induced by Severe Acute Pancreatitis

Aim

To reveal the role of bacterial translocation (BT) and autophagy in severe acute pancreatitis-induced acute lung injury (SAP-ALI).

Methods

Rats were separated into a control (sham-operation) group (n = 10) and a SAP group (n = 10) and a SAP group (

Results

Levels of TNF-α, IL-6, lipase, and amylase in the SAP group were significantly higher than those in the control group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (P < 0.01). Histopathological score and W/D ratio of the lung in the SAP-BT(+) group were significantly higher than that in the SAP-BT(-) group (

Conclusions

BT can aggravate SAP-ALI with the increasing oxidative stress level, which may be related to the decrease of autophagy level.

Efficacy of enteral glutamine supplementation in patients with severe and predicted severe acute pancreatitis- A randomized controlled trial

BACKGROUND

In severe acute pancreatitis (AP), intravenous glutamine has been shown to reduce the rate of complications, hospital stay, and mortality. In the present randomized trial, we aimed to evaluate the effect of enteral glutamine supplementation on clinical outcomes, gut permeability, systemic inflammation, oxidative stress, and plasma glutamine levels in patients with severe and predicted severe AP.

METHODS

Patients with AP admitted within 72 h of onset of symptoms were included. The primary outcome measure was development of infected pancreatic and peri-pancreatic necrosis and in-hospital mortality. High-sensitivity C-reactive protein (HS-CRP) and interleukin-6 (IL-6) were evaluated as markers of inflammation; plasma thiobarbituric acid reactive substances (TBARS) and activities of serum superoxide dismutase and glutathione peroxidase were determined to evaluate oxidative stress; serum polyethylene glycol (PEG) was tested for intestinal permeability; subjective global assessment (SGA) was used for nutritional assessment, and an improvement in organ function was measured by the Modified Marshall score. Intention-to-treat analysis was used. A p-value of < 0.05 was considered statistically significant.

RESULTS

After power calculation, we enrolled 18 patients in the glutamine and 22 in the control arm. There was no significant improvement in the development of infected necrosis and in-hospital mortality between the groups. Improvement in Modified Marshall score was observed in a higher proportion of patients receiving glutamine (15 [83.3%] vs. 12 [54.5%]; p = 0.05). Plasma glutamine levels improved more in glutamine-treated group (432.72 ± 307.83 vs. 618.06 ± 543.29 μM/L; p = 0.004), while it was lower in controls (576.90 ± 477.97 vs. 528.20 ± 410.45 μM/L; p = 0.003). PEG level was lower after glutamine supplementation (39.91 ± 11.97 vs. 32.30 ± 7.39 ng/mL; p = 0.02). Statistically significant reduction in IL-6 concentration was observed in the glutamine group at the end of treatment (87.44 ± 7.1 vs. 63.42 ± 33.7 μM/L; p = 0.02).

CONCLUSIONS

Despite absence of improvement in infected necrosis and in-hospital mortality, enteral glutamine supplementation showed improvement in gut permeability, oxidative stress, and a trend towards improvement in organ function as depicted by improvement in the Modified Marshall score.

TRIAL REGISTRATION

NCT01503320.

Gut microbiota dysbiosis worsens the severity of acute pancreatitis in patients and mice

BACKGROUND

The gut is implicated in the pathogenesis of acute pancreatitis (AP) and the infectious complications of AP are commonly associated with enteric bacteria, yet whether gut microbiota dysbiosis participants in AP severity remains largely unknown.

METHODS

We collected clinical information and fecal samples from 165 adult participants, including 41 with mild AP (MAP), 59 with moderately severe AP (MSAP), 30 with severe AP (SAP) and 35 healthy controls (HC). The serum inflammatory cytokines and gut barrier indexes were detected. Male C57BL/6 mice with AP were established and injuries of pancreas were evaluated in antibiotic-treated mice, germ-free mice as well as those transplanted with fecal microbiota. The gut microbiota was analyzed by 16S rRNA gene sequencing.

RESULTS

The structure of gut microbiota was significantly different between AP and HC, and the disturbed microbiota was closely correlated with systematic inflammation and gut barrier dysfunction. Notably, the microbial composition changed further with the worsening of AP and the abundance of beneficial bacteria such as Blautia was decreased in SAP compared with MAP and MSAP. The increased capacity for the inferred pathway, bacterial invasion of epithelial cells in AP, highly correlated with the abundance of Escherichia-Shigella. Furthermore, the antibiotic-treated mice and germ-free mice exhibited alleviated pancreatic injury after AP induction and subsequent fecal microbiota transplantation in turn exacerbated the disease.

CONCLUSIONS

This study identifies the gut microbiota as an important mediator during AP and its dysbiosis is associated with AP severity, which suggests its role as potential therapeutic target.

Bacterial community mapping of the intestinal tract in acute pancreatitis rats based on 16S rDNA gene sequence analysis

Numerous studies have revealed that the status of intestinal microbiota has a marked impact on inflammation, which may progressively aggravate the systemic inflammatory response caused by acute pancreatitis (AP).

Quantitative Measure of Intestinal Permeability Using Blue Food Coloring

BACKGROUND

Loss of intestinal barrier integrity plays a fundamental role in the pathogenesis of various gastrointestinal diseases and is implicated in the onset of sepsis and multiple organ failure. An array of methods to assess different aspects of intestinal barrier function suffers from lack of sensitivity, prolonged periods of specimen collection, or high expense. We have developed a technique to measure the concentration of the food dye FD&C Blue #1 from blood and sought to assess its utility in measuring intestinal barrier function in humans.

MATERIALS AND METHODS

Four healthy volunteers and 10 critically ill subjects in the intensive care unit were recruited in accordance with an institutional review board approved protocol. Subjects were given 0.5 mg/kg Blue #1 enterally as an aqueous solution of diluted food coloring. Five blood specimens were drawn per subject: 0 h (before dose), 1, 2, 4, and 8 h. After plasma isolation, organic extracts were analyzed by high-performance liquid chromatography/mass spectrometry detecting the presence of unmodified dye.

RESULTS

We found no baseline detectable absorption in healthy volunteers. After including the subjects in the intensive care unit, we compared dye absorption in the six subjects who met criteria for septic shock with the eight who did not. Septic patients demonstrated significantly greater absorption of Blue #1 after 2 h.

CONCLUSIONS

We have developed a novel, easy-to-use method to measure intestinal barrier integrity using a food grade dye detectable by mass spectrometry analysis of patient blood following oral administration.

Prophylaxis for Stress Ulcers With Proton Pump Inhibitors Is Not Associated With Increased Risk of Bloodstream Infections in the Intensive Care Unit

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) have been associated with increased risk of infection, likely because of changes in intestinal epithelial permeability and the gastrointestinal microbiome. PPIs are frequently given to patients in the intensive care unit (ICU) to prevent stress ulcers. These patients are at risk for bloodstream infections (BSIs), so we investigated the relationship between PPI use and BSIs among patients in the ICU.

METHODS

We performed a retrospective cohort study of adults (≥18 years) admitted to 1 of 14 ICUs within a hospital network of 3 large hospitals from 2008 through 2014. The primary exposure was PPI use for stress ulcer prophylaxis in the ICU. The primary outcome was BSI, confirmed by culture analysis, arising 48 hours or more after admission to the ICU. Subjects were followed for 30 days after ICU admission or until death, discharge, or BSI. Multivariable Cox proportional hazards modeling was used to test the association between PPIs and BSI after controlling for patient comorbidities and other clinical factors.

RESULTS

We analyzed data from 24,774 patients in the ICU, including 756 patients (3.1%) who developed BSIs while in the ICU. The cumulative incidence of BSI was 3.7% in patients with PPI exposure compared with 2.2% in patients without PPI exposure (log-rank test, P < .01). After adjusting for potential confounders, PPI exposure was not associated with increased risk of BSI while in the ICU (adjusted hazard ratio, 1.08; 95% confidence interval, 0.91-1.29). Comorbidities, antibiotic use, and mechanical ventilation were all independently associated with increased risk for BSIs.

CONCLUSIONS

In a retrospective study of patients in the ICU, administration of PPIs to prevent bleeding was not associated with increased risk of BSI. These findings indicate that concern for BSI should not affect decisions regarding use of PPIs in the ICU.

Mechanism of Increased Intestinal Permeability in Acute Pancreatitis: Alteration in Tight Junction Proteins

BACKGROUND AND AIMS

Intestinal permeability (IP) has been shown to be increased in acute pancreatitis (AP) and is considered to be responsible for development of septic complications. However, the mechanism of increase in IP is not well studied. We studied whether alteration in tight junction proteins (TJP) has any role in altered IP in patients with AP.

MATERIALS AND METHODS

This is a prospective study conducted at a tertiary care referral center. Twenty consecutive moderate and severe AP patients fulfilling the study criteria were included along with 20 controls that underwent gastroduodenoscopy for dyspepsia. IP was measured with lactulose mannitol (LM) ratio and TJP were studied by measuring expression of claudin-2 and claudin-4 in duodenal biopsy samples. Statistical analysis was done with STATA 13.0.

RESULTS

IP as depicted by LM ratio was significantly higher in AP patients as compared with controls (4.659±10.4 vs. 0.101±0.297; P<0.001). Claudin-4 expression was reduced in duodenal biopsies in AP patients (P<0.001 for crypt intercellular junction and P=0.007 for crypt cytoplasm). However, LM ratio was not associated with either mortality (P=0.12) or development of infected pancreatic necrosis (P=0.3).

CONCLUSIONS

IP is increased in AP. Alteration in TJP in the form of reduced claudin-4 expressions could be the possible mechanism for increased IP.

Effect of mesenchymal stem cells on small intestinal injury in a rat model of acute necrotizing pancreatitis

BACKGROUND

Acute necrotizing pancreatitis (ANP) is often complicated by multiple organ failure. The small intestine is frequently damaged during ANP. Capillary leakage in multiple organs during ANP is one of the most important causes of multiple organ dysfunction. Damage to the capillary endothelial barrier and impaired water transportation could lead to capillary leakage in ANP.

METHODS

Sprague-Dawley (SD) rats were randomized into a control group, the ANP group, the culture media-treated group, or the bone marrow-derived mesenchymal stem cell (BMSC)-treated group (30 rats in each group). Ten rats in each group were sacrificed at 6, 12, and 24 h after induction of experimental models. Serum, ascites, pancreatic, and small intestinal samples were collected. The levels of serum and ascites albumin and amylases were measured, pancreatic histology was assessed, and the connection changes between vessel endothelial cells were evaluated using scanning electron microscopy (SEM). Capillary leakage in small intestinal tissue was observed visually by tracking fluorescein isothiocyanate (FITC)-albumin, and was measured by the Evans blue extravasation method. The location and expression of aquaporin 1 (AQP1) in the small intestine was analyzed using immunohistochemistry, real-time polymerase chain reaction (PCR), and Western blot.

RESULTS

The outcomes showed that the level of serum and ascites amylase is elevated. Conversely, the level of serum albumin is decreased while ascites albumin is elevated. There is damage to pancreatic tissue, and the small intestinal capillary endothelial barrier was aggravated. Furthermore, the expression of AQP1 was reduced significantly after induced ANP. Following treatment with MSCs, the elevation of amylase and the decrease of serum albumin were inhibited, the damage to pancreatic tissue and the level of small intestinal capillary leakage was alleviated, and the downregulation of AQP1 was reversed.

CONCLUSIONS

In conclusion, MSC therapy could alleviate small intestinal injury in rats with ANP, the mechanism of which might be related to reduction of damage to the small intestinal capillary endothelial barrier, and increased expression of AQP1 in the small intestine.

Role of liver in modulating the release of inflammatory cytokines involved in lung and multiple organ dysfunction in severe acute pancreatitis

The objective of this study was to understand the role of liver in modulating remote organ dysfunction during severe acute pancreatitis (SAP). We used sodium taurocholate and endotoxin to induce SAP in the rats and confirmed the development of this condition by measuring serum and ascite levels of the biomarkers of liver and lung damage. Our results showed that expression of tumor necrosis factor (TNF)-α was up-regulated sequentially, first in the gut, then in the liver, and finally in lung. Moreover, the SAP-induced increase in the expressions of TNF-α and IL-6 occurring in gut, liver, and lung was directly related to the increase in time. However, in liver and lung, the transcriptional activity of NF-κB and expression of TNF-α at 4 and 8 h were not increased. The distribution sequence of the pro-inflammatory cytokines to various organs was determined by their detection in the blood from portal vein and inferior vena cava. Although liver received TNF-α during 0.5-8 h of the SAP induction, the release of this cytokine into vena cava was not increased in this period of time. In conclusion, our results suggest that the aggravation of SAP leading to development of MODS exhibited the gut-liver-lung cytokine axis. Furthermore, this study indicates that liver performs both protective and stimulatory activities in the modulation of pro-inflammatory cytokine generation and their distribution to remote organs, such as lungs.

Severe Acute Pancreatitis: Gut Barrier Failure, Systemic Inflammatory Response, Acute Lung Injury, and the Role of the Mesenteric Lymph

BACKGROUND

Severe acute pancreatitis (AP) often leads to distant organ dysfunction with a high morbidity and mortality rate. The most common and earliest organ to fail is the lungs, but the exact pathophysiological mechanisms underlying the disease are still unclear. No successful targeted therapy exists, and treatment is limited to organ supportive care. It is believed that the gut is involved in the development of distant organ failure, as severe AP is associated with changes in the microcirculation, gut permeability/motility, bacterial translocation, and activation of the gut-associated lymphoid tissue (GALT). Experimental evidence implicates the mesenteric lymph as a primary route for these toxic factors to gain access to the systemic circulation. This literature overview was made to survey these mechanisms and the potential of surgical interventions on the thoracic duct as a means of therapy.

METHODS

Review of the pertinent English-language literature.

RESULTS

In experimental studies, interruption of mesenteric lymphatic flow has preventive qualities for acute lung injury (ALI) in the setting of critical illness with various etiologies. Experimentally, diversion of mesenteric lymph is able to prevent ALI if done before its development, whereas a later intervention partially reduces the lung damage. Few studies have investigated surgical approaches to the thoracic duct in human beings under these circumstances, and the ones that have been performed are of low quality and have conflicting results. It seems likely that the intervention would need to be performed prior to the development of ALI to obtain maximum benefits, which complicates its application clinically, because prediction of ALI cannot today be done with high precision.

CONCLUSION

Studies are ongoing to identify the factors carried in mesenteric lymph that may cause end-organ failure (e.g., ALI) and, once recognized, might allow the development of novel targeted agents that would modify the disease course.

Intestinal permeability defects: is it time to treat?

An essential role of the intestinal epithelium is to separate luminal contents from the interstitium, a function primarily determined by the integrity of the epithelium and the tight junction that seals the paracellular space. Intestinal tight junctions are selectively permeable, and intestinal permeability can be increased physiologically in response to luminal nutrients or pathologically by mucosal immune cells and cytokines, the enteric nervous system, and pathogens. Compromised intestinal barrier function is associated with an array of clinical conditions, both intestinal and systemic. Although most available data are correlative, some studies support a model where cycles of increased intestinal permeability, intestinal immune activation, and subsequent immune-mediated barrier loss contribute to disease progression. This model is applicable to intestinal and systemic diseases. However, it has not been proven, and both mechanistic and therapeutic studies are ongoing. Nevertheless, the correlation between increased intestinal permeability and disease has caught the attention of the public, leading to a rise in popularity of the diagnosis of "leaky gut syndrome," which encompasses a range of systemic disorders. Proponents claim that barrier restoration will cure underlying disease, but this has not been demonstrated in clinical trials. Moreover, human and mouse studies show that intestinal barrier loss alone is insufficient to initiate disease. It is therefore uncertain whether increased permeability in these patients is a cause or effect of the underlying disorder. Although drug targets that may mediate barrier restoration have been proposed, none have been proven effective. As such, current treatments for barrier dysfunction should target the underlying disease.

Role of the gut barrier in acute pancreatitis

The small intestine is one of the distant organs that become damaged during severe acute pancreatitis, due to microcirculation disturbance associated with loss of fluids in the "third space," hypovolemia, splanchnic vasoconstriction, and finally an ischemia-reperfusion injury. In this scenario, the gut acts as the starter for severe systemic complications, as the failure of the intestinal barrier is associated with translocation of bacteria and inflammatory and toxic products produced in the intestinal wall, which can be responsible for sepsis and infection of the necrotic pancreas and for systemic inflammatory response. Therefore, one of the main goals of treatment in the early phases of severe acute pancreatitis should be to maintain the integrity of the gut barrier in the small intestine. These strategies include appropriate fluid resuscitation to limit the damage due to the relative hypovolemia and early enteral feeding. The role of intravenous antibiotics to prevent infection of the pancreatic necrosis is controversial and the role of probiotics, which seemed a promising tool in vitro and in early clinical trials, needs to be further investigated to better understand the effects of the single specific strains at various doses and timing before designing new clinical trials.

Emodin promoted pancreatic claudin-5 and occludin expression in experimental acute pancreatitis rats

AIM: To investigate the effect of emodin on pancreatic claudin-5 and occludin expression, and pancreatic paracellular permeability in acute pancreatitis (AP).

METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 0 or 6 h after induction of AP. Rats from sham operation and AP groups were injected with normal saline at the same time. Samples of pancreas were obtained 6 or 12 h after drug administration. Pancreatic morphology was examined with hematoxylin and eosin staining. Pancreatic edema was estimated by measuring tissue water content. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 level were measured by enzyme-linked immunosorbent assay. Pancreatic paracellular permeability was assessed by tissue dye extravasation. Expression of pancreatic claudin-5 and occludin was examined by immunohistology, quantitative real-time reverse transcriptase polymerase chain reaction and western blotting.

RESULTS: Pancreatic TNF-α and IL-6 levels, wet/dry ratio, dye extravasation, and histological score were significantly elevated at 3, 6 and 12 h following sodium taurocholate infusion; treatment with emodin prevented these changes at all time points. Immunostaining of claudin-5 and occludin was detected in rat pancreas, which was distributed in pancreatic acinar cells, ductal cells and vascular endothelial cells, respectively. Sodium taurocholate infusion significantly decreased pancreatic claudin-5 and occludin mRNA and protein levels at 3, 6 and 12 h, and that could be promoted by intravenous administration of emodin at all time points.

CONCLUSION: These results demonstrate that emodin could promote pancreatic claudin-5 and occludin expression, and reduce pancreatic paracellular permeability.

The effect of intra-abdominal hypertension incorporating severe acute pancreatitis in a porcine model

Introduction

Abdominal compartment syndrome (ACS) and intra abdominal hypertension(IAH) are common clinical findings in patients with severe acute pancreatitis(SAP). It is thought that an increased intra abdominal pressure(IAP) is associated with poor prognosis in SAP patients. But the detailed effect of IAH/ACS on different organ system is not clear. The aim of this study was to assess the effect of SAP combined with IAH on hemodynamics, systemic oxygenation, and organ damage in a 12 h lasting porcine model.

Measurements and Methods

Following baseline registrations, a total of 30 animals were divided into 5 groups (6 animals in each group): SAP+IAP30 group, SAP+IAP20 group, SAP group, IAP30 group(sham-operated but without SAP) and sham-operated group. We used a N₂ pneumoperitoneum to induce different levels of IAH and retrograde intra-ductal infusion of sodium taurocholate to induce SAP. The investigation period was 12 h. Hemodynamic parameters (CO, HR, MAP, CVP), urine output, oxygenation parameters(e.g., S_vO₂, PO₂, PaCO₂), peak inspiratory pressure, as well as serum parameters (e.g., ALT, amylase, lactate, creatinine) were recorded. Histological examination of liver, intestine, pancreas, and lung was performed.

Main Results

Cardiac output significantly decreased in the SAP+IAH animals compared with other groups. Furthermore, AST, creatinine, SUN and lactate showed similar increasing tendency paralleled with profoundly decrease in S_vO₂. The histopathological analyses also revealed higher grade injury of liver, intestine, pancreas and lung in the SAP+IAH groups. However, few differences were found between the two SAP+IAH groups with different levels of IAP.

Conclusions

Our newly developed porcine SAP+IAH model demonstrated that there were remarkable effects on global hemodynamics, oxygenation and organ function in response to sustained IAH of 12 h combined with SAP. Moreover, our model should be helpful to study the mechanisms of IAH/ACS-induced exacerbation and to optimize the treatment strategies for counteracting the development of organ dysfunction.

Vasoactive intestinal peptide promotes gut barrier function against severe acute pancreatitis

To explore the influence of vasoactive intestinal peptide (VIP) on the gut barrier function in severe acute pancreatitis (SAP). Fifty four SD rats were randomly divided into three groups: sham operated (SO) group, SAP group and VIP intervention group. Each group was further divided into three time points: 1, 6 and 12 h after operation with 6 rats for each treatment point. SAP models were induced by retrograde injection of 4% sodium taurocholate into the bili-pancreatic duct. VIP intervention group was made by 5 nmol VIP intraperitoneal injection within 5 min after SAP model successfully obtained. The VIP in plasma and intestinal homogenate were detected with ELISA. The endotoxin in plasma of all groups was also tested. The expression levels of TLR4, TNF-α, IL-6, and IL-10 in gut mucosa were measured by RT-PCR. Meanwhile intestinal samples were harvested for pathological examination. Compared to SO group, the VIP in plasma and intestinal homogenate of SAP group were significantly decreased at 1 h after induction, and then gradually increased to beyond the level of SO group at 12 h. The endotoxin of SAP group was continually increased. The mRNA levels of TLR4, TNF-α, IL-6, and IL-10 were also increased with obvious pathological injuries in the intestine. In the VIP group, endotoxin in plasma was obviously decreased compared to SAP group. The expressions of TNF-α, IL-6 mRNA were suppressed while IL-10mRNA was increased. The intestinal pathological injuries were also markedly alleviated. These results suggested that VIP had protective effects on SAP gut barrier function through inhibiting intestinal mucosal inflammatory responses.

Effects of enteral immunonutrition on the maintenance of gut barrier function and immune function in pigs with severe acute pancreatitis

BACKGROUND

This study evaluated the effects of enteral immunonutrition (EIN) supplemented with glutamine, arginine, and probiotics on gut barrier function and immune function in pigs with severe acute pancreatitis (SAP).

METHODS

The model was induced by retrograde injection of 5% sodium taurocholate and trypsin via the pancreatic duct. After induction of SAP, 18 pigs were randomly divided into 3 groups, in which either parenteral nutrition (PN), control enteral nutrition (CEN), or EIN was applied for 8 days. Serum and pancreatic fluid amylase concentration was determined. Intestinal permeability (lactulose to mannitol ratio) was measured by high-performance liquid chromatography, and plasma endotoxin was quantified by the chromogenic limulus amebocyte lysate technique. Samples of venous blood and organs were cultured using standard techniques. Pancreatitis severity and villi of ileum were scored according to histopathologic grading. Plasma T-lymphocyte subsets were measured by flow cytometry, and immunoglobulins (Igs) were determined via enzyme-linked immunosorbent assay.

RESULTS

There were no significant differences in serum and pancreatic fluid amylases concentrations or in pancreatitis severity between any 2 of the 3 groups. Compared with PN and CEN, EIN significantly decreased intestinal permeability, plasma endotoxin concentration, and the incidence and magnitudes of bacterial translocation, but increased ileal mucosal thickness, villous height, crypt depth, and percentage of normal intestinal villi. Significant differences were found in CD3+, CD4+ lymphocyte subsets, the ratio of CD4+: CD8+ lymphocyte subsets, and serum IgA and IgG, but not IgM, between any 2 of the 3 groups.

CONCLUSIONS

EIN maintained gut barrier function and immune function in pigs with SAP.

Non-invasive assessment of barrier integrity and function of the human gut

Over the past decades evidence has been accumulating that intestinal barrier integrity loss plays a key role in the development and perpetuation of a variety of disease states including inflammatory bowel disease and celiac disease, and is a key player in the onset of sepsis and multiple organ failure in situations of intestinal hypoperfusion, including trauma and major surgery. Insight into gut barrier integrity and function loss is important to improve our knowledge on disease etiology and pathophysiology and contributes to early detection and/or secondary prevention of disease. A variety of tests have been developed to assess intestinal epithelial cell damage, intestinal tight junction status and consequences of intestinal barrier integrity loss, i.e. increased intestinal permeability. This review discusses currently available methods for evaluating loss of human intestinal barrier integrity and function.

Enteral versus parenteral nutrition for acute pancreatitis

BACKGROUND

Acute pancreatitis creates a catabolic stress state promoting a systemic inflammatory response and nutritional deterioration. Adequate supply of nutrients plays an important role in recovery. Total parenteral nutrition (TPN) has been standard practice for providing exogenous nutrients to patients with severe acute pancreatitis. However, recent data suggest that enteral nutrition (EN) is not only feasible, but safer and more effective.Therefore, we sought to update our systematic review to re-evaluate the level of evidence.

OBJECTIVES

To compare the effect of TPN versus EN on mortality, morbidity and length of hospital stay in patients with acute pancreatitis.

SEARCH STRATEGY

Trials were identified by computerized searches of The Cochrane Controlled Trials Register, MEDLINE, and EMBASE. Additional studies were identified by searching Scisearch, bibliographies of review articles and identified trials. The search was undertaken in August 2000 and updated in September 2002, October 2003, November 2004 and November 2008. No language restrictions were applied.

SELECTION CRITERIA

Randomized clinical trials comparing TPN to EN in patients with acute pancreatitis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. A standardized form was used to extract relevant data.

MAIN RESULTS

Eight trials with a total of 348 participants were included. Comparing EN to TPN for acute pancreatitis, the relative risk (RR) for death was 0.50 (95% CI 0.28 to 0.91), for multiple organ failure (MOF) was 0.55 (95% CI 0.37 to 0.81), for systemic infection was 0.39 (95% CI 0.23 to 0.65), for operative interventions was 0.44 (95% CI 0.29 to 0.67), for local septic complications was 0.74 (95% CI 0.40 to 1.35), and for other local complications was 0.70 (95% CI 0.43 to 1.13). Mean length of hospital stay was reduced by 2.37 days in EN vs TPN groups (95% CI -7.18 to 2.44). Furthermore, a subgroup analysis for EN vs TPN in patients with severe acute pancreatitis showed a RR for death of 0.18 (95% CI 0.06 to 0.58) and a RR for MOF of 0.46 (95% CI 0.16 to 1.29).

AUTHORS' CONCLUSIONS

In patients with acute pancreatitis, enteral nutrition significantly reduced mortality, multiple organ failure, systemic infections, and the need for operative interventions compared to those who received TPN. In addition, there was a trend towards a reduction in length of hospital stay. These data suggest that EN should be considered the standard of care for patients with acute pancreatitis requiring nutritional support.

Acute stress increases colonic paracellular permeability in mice through a mast cell-independent mechanism: involvement of pancreatic trypsin

AIMS

Increased colonic paracellular permeability (CPP) is a key feature of gastro-intestinal disorders as irritable bowel syndrome and inflammatory bowel diseases. Stress stimulates exocrine pancreatic secretion through cholinergic pathways, and trypsin is known to increase CPP. Consequently we have investigated in this work whether trypsin released into the gut lumen following an acute stress may participate to the short-term increase in CPP.

MAIN METHODS

Mice were treated with atropine or a non-selective CRF (corticotropin-releasing factor) receptor antagonist (alpha-helical CRF (9-41)), before being submitted to a 2-h stress session. Then, CPP and protease activity in colonic contents (total proteolytic, trypsin activity, and mouse mast cell protease (MMCP)-1 levels) were determined. The effects of colonic contents from sham-stressed or stressed animals on CPP were evaluated in mice colonic tissues mounted in Ussing chambers, in presence or not of soybean trypsin inhibitor (SBTI) or FSLLRY, a protease-activated receptor-2 (PAR2) antagonist.

KEY FINDINGS

Acute stress significantly increased CPP, proteolytic and trypsin activities, and MMCP-1 levels. Atropine inhibited stress-induced impairment of CPP and strongly diminished total proteolytic and trypsin activities in stressed animals, but not MMCP-1 levels. Colonic contents from stressed animals increased CPP in mice tissues, this effect being inhibited by SBTI and PAR2 antagonist.

SIGNIFICANCE

Acute stress activates cholinergic pathways, to trigger exocrine pancreatic secretion. Trypsin, released in these conditions, may be responsible for colonic barrier alterations through the activation of PAR2.

Effects of gut barrier dysfunction and NF-kappaB activation on aggravating mechanism of severe acute pancreatitis

OBJECTIVE

To study the effects of gut-derived endotoxin translocation and NF-kappaB activation on the aggravating mechanism of severe acute pancreatitis (SAP) and of treatment with pyrrolidine dithiocarbamate (PDTC) on rats with SAP.

METHODS

SD rats were randomly divided into sham operation group (SO), SAP group, SAP + lipopolysaccharide(LPS) group, pyrrolidine dithiocarbamate (PDTC) treatment group and LPS group. Biochemical parameters and cytokines were examined in the serum. Multiple organs pathological slices were examined. Expression of NF-kappaB mRNA in the liver tissue was detected by RT-PCR. Activation of NF-kappaB by the method of streptomycin avidin-peroxidase (SP) and expression of NF-kappaB p65 protein and its binding activity were analyzed by Western blot and electrophoretic mobidity shift assay (EMSA).

RESULTS

Compared with sham operation group, the concentration of TNF-alpha, alanine aminotransferase (ALT), and diamine oxidase (DAO) in serum significantly increased in SAP + LPS group (P < 0.05). Pathological changes were markedly observed in tissues and the expression of NF-kappaB mRNA in the liver significantly increased (P < 0.05) also, the activation of NF-kappaB and binding activity of NF-kappaB p65 protein in the liver markedly increased (P < 0.01) in SAP + LPS group. Treatment with PDTC markedly reduced concentration of ALT, DAO and TNF-alpha, and the expression of NF-kappaB, and the pathologic scores, as well as significantly decreased the expression of NF-kappaB p65 protein.

CONCLUSION

The activation and overexpression of NF-kappaB may participate in the aggravating mechanism of SAP. Treatment with PDTC has a protective effect on multiple organs damage in SAP.

Early gut mucosal dysfunction in patients with acute pancreatitis

OBJECTIVES

A clinical study was made to test the hypothesis that gut mucosal damage happens and correlates with endotoxemia, systemic inflammation, severity of disease, septic complication, and outcome in acute pancreatitis (AP) patients.

METHODS

Patients were divided into 3 groups according to severity: grade 1 (n = 26, mild), grade 2 (n = 18, severe AP [SAP] without organ dysfunction), and grade 3 (n = 18, SAP with organ dysfunction). Twenty healthy volunteers were enrolled as control group. The intestinal lactulose and mannitol absorption ratio, d-xylose absorption, endotoxin, and tumor necrosis factor alpha were detected in parallel to clinical data collection.

RESULTS

Lactulose and mannitol absorption ratio increased in patients with AP, and the increase was more pronounced in SAP (grade 1: 0.044 +/- 0.017, grade 2: 0.39 +/- 0.16, grade 3: 0.48 +/- 0.22, control: 0.024 +/- 0.009; P < 0.01 between control and AP, P < 0.01 between mild and severe group). d-Xylose absorption decreased in pancreatitis groups (P < 0.01) especially in severe groups (P < 0.01 between mild and SAP). We also observed a significant positive correlation of mucosal permeability with endotoxin (r = 0.902, P < 0.001) and tumor necrosis factor alpha changes (r = 0.862, P < 0.001). The severity and septic complication in AP patients were different accompanied with severity of gut mucosal damage.

CONCLUSIONS

Intestinal mucosal function is injured in early phase of AP especially in patients with organ dysfunction, which may be a stimulus for development of multiple organ dysfunction and correlate with bad outcome in AP patients.

Up-regulation of Toll-like receptor 4 was suppressed by emodin and baicalin in the setting of acute pancreatitis

Acute pancreatitis (AP) activates the systemic inflammatory response and is potentially lethal. Recent studies demonstrated that pancreatic enzymes could induce cytokine expression via Toll-like receptor 4 (TLR4) signal pathway, indicating a possible role of TLR4 in local pancreatic injury and systemic inflammatory response. Emodin, an anthraquinone derivative from Radix et Rhizoma Rhei, and baicalin, a flavone from Scutellaria baicalensis Georgi, both have been reported to possess anti-inflammatory activities. In present study, we investigated the combined effect of emodin and baicalin on pancreatic damage and pancreatitis associated lung injury, as well as tissue TLR4 expression in the setting of AP. The results showed that combination of emodin and baicalin significantly reduced serum amylase, tumor necrosis factor-alpha and interleukin-6, attenuated pancreatic and pulmonary damage, also suppressed TLR4 expression in pancreas and lung. It could be speculated that amelioration of pancreatic and pulmonary damage by emodin and baicalin might contribute, in part at least, to the suppression of TLR4 expression. The present study provides beneficial evidence as to simultaneous treatment for AP, and also suggests an important role of TLR4 in pathophysiology of AP.

Acute pancreatitis severity is exacerbated by intestinal ischemia-reperfusion conditioned mesenteric lymph

OBJECTIVE

To determine the effect of intestinal ischemia-reperfusion (IIR) on acute pancreatitis (AP) and the role of mesenteric lymph.

SUMMARY BACKGROUND DATA

Intestinal ischemia is an early feature of AP and is related to the severity of disease. It is not known whether this contributes to the severity of AP or is a consequence.

METHODS

Two experiments are reported here using intravital microscopy and a rodent model of mild acute pancreatitis (intraductal 2.5% sodium taurocholate). In the first, rats had an episode of IIR during AP that was produced by temporary occlusion of the superior mesenteric artery (30 min or 3 x 10 min) followed by 2h reperfusion. In a second study rats with AP had an intravenous infusion of mesenteric lymph collected from donor rats that had been subjected to IIR. In both experiments the pancreatic erythrocyte velocity (EV), functional capillary density (FCD), leukocyte adherence (LA), histology and edema index were measured.

RESULTS

The addition of IIR to AP caused a decline in the pancreatic microcirculation greater than that of AP alone (EV 42% of baseline vs. 73% of baseline AP alone, FCD 43% vs 72%, LA 7 fold increase vs 4 fold increase). This caused an increased severity of AP as evidenced by 1.4-1.8 fold increase of pancreatic edema index and histologic injury respectively. A very similar exacerbation of microvascular failure and increased pancreatitis severity was then demonstrated by the intravenous infusion of IIR conditioned mesenteric lymph from donor animals.

CONCLUSIONS

Unidentified factors released into the mesenteric lymph following IIR injury are capable of exacerbating AP. This highlights an important role for the intestine in the pathophysiology of AP pathogenesis and identifies mesenteric lymph as a potential therapeutic target.

New advances in pancreatic surgery

PURPOSE OF REVIEW

New understanding of the dynamic of acute pancreatitis, the clinical impact of local pathology in chronic pancreatitis and cystic neoplastic lesions bearing high potential for malignant transformation has changed the management of pancreatic diseases.

RECENT FINDINGS

In acute pancreatitis, risk factors independently determining outcome in severe acute pancreatitis are early and persistent multiorgan failure, infected necrosis and extended sterile necrosis. The management of severe acute pancreatitis is based on early intensive-care treatment and late surgical debridement. In chronic pancreatitis, recent data from randomized controlled clinical trials have demonstrated duodenum-preserving pancreatic head resection with an inflammatory mass of the head as superior to pylorus-preserving Whipple resection. Cystic neoplasms are local lesions of the pancreas with high malignant potential. Local organ-preserving resection techniques have been applied with low morbidity and mortality, replacing a Whipple-type resection. Resection of pancreatic cancer is ineffective to cure patients. After an R0-resection, a significant survival benefit has been achieved when adjuvant chemotherapy has additionally been applied.

SUMMARY

New knowledge about the nature of inflammatory diseases, cystic neoplastic lesions and malignant pancreatic tumours has changed the indication for surgical treatment and the application of organ-preserving surgical techniques.

Lactate and glycerol released to the intestinal lumen reflect mucosal injury and permeability changes caused by strangulation obstruction

BACKGROUND

The present study evaluates whether microdialysis of glycerol and lactate reflects mucosal injury and permeability changes after strangulation obstruction of the pig small intestine.

METHODS

Strangulation obstruction was induced by tightening a rubber band around a small bowel loop until its venous pressure increased to a level just below diastolic aortic pressure (partial strangulation), or further until cessation of flow in the main feeding artery (total strangulation). Mucosal injury and permeability of marker molecules from blood to lumen and vice versa was compared to release of glycerol and lactate to the intestinal lumen.

RESULTS

Mucosal injury, hyperpermeability, and release of glycerol were more pronounced after total than after partial strangulation. In animals with partial strangulation there was a complete restitution of the surface epithelium, and luminal glycerol and lumen-to-blood permeability of polyethylene glycol 4000 remained low. Such animals showed a sustained elevation of lactate and blood-to-lumen permeability of fluorescein isothiocyanate dextran after 2 h of partial strangulation, but a decline to baseline levels of these parameters in animals with 1 h partial strangulation.

CONCLUSION

Microdialysis of lactate and glycerol in the intestinal lumen may be used to assess structural and functional changes of the intestinal mucosa after strangulation obstruction.

Early nasogastric feeding in predicted severe acute pancreatitis: A clinical, randomized study

OBJECTIVE

To compare the efficacy and safety of early, nasogastric enteral nutrition (EN) with total parenteral nutrition (TPN) in patients with predicted severe acute pancreatitis (SAP).

SUMMARY BACKGROUND DATA

In SAP, the magnitude of the inflammatory response as well as increased intestinal permeability correlates with outcome. Enteral feeding has been suggested superior to parenteral feeding due to a proposed beneficial effect on the gut barrier.

METHODS

Fifty patients who met the inclusion criteria were randomized to TPN or EN groups. The nutritional regimen was started within 24 hours from admission and EN was provided through a nasogastric tube. The observation period was 10 days. Intestinal permeability was measured by excretion of polyethylene glycol (PEG) and concentrations of antiendotoxin core antibodies (Endocab). Interleukins (IL)-6 IL-8, and C-reactive protein (CRP) were used as markers of the systemic inflammatory response. Morbidity and feasibility of the nutritional route were evaluated by the frequency of complications, gastrointestinal symptoms, and abdominal pain.

RESULTS

PEG, Endocab, CRP, IL-6, APACHE II score, severity according to the Atlanta classification (22 patients), and gastrointestinal symptoms or abdominal pain did not significantly differ between the groups. The incidence of hyperglycemia was significantly higher in TPN patients (21 of 26 vs. 7 of 23; P < 0.001). Total complications (25 vs. 52; P = 0.04) and pulmonary complications (10 vs. 21; P = 0.04) were significantly more frequent in EN patients, although complications were diagnosed dominantly within the first 3 days.

CONCLUSION

In predicted SAP, nasogastric early EN was feasible and resulted in better control of blood glucose levels, although the overall early complication rate was higher in the EN group. No beneficial effects on intestinal permeability or the inflammatory response were seen by EN treatment.

Breakdown of intestinal mucosa via accelerated apoptosis increases intestinal permeability in experimental severe acute pancreatitis

BACKGROUND

Bacterial translocation plays an important role for infectious complications in severe acute pancreatitis (SAP). Breakdown of intestinal mucosal integrity may increase intestinal permeability and may be implicated in bacterial translocation. It is suggested that increase in intestinal permeability is correlated with the changes of tight junction and/or apoptosis in intestinal epithelial cells. The aim of this study was to investigate the changes of intestinal mucosa and its permeability in SAP.

METHODS

SAP was induced by injection of 3% sodium deoxycholate into the biliopancreatic ducts in rats. Permeability of intestinal wall was assayed ex vivo by measuring the leaked amount of FITC-dextran from the ileum pouch. Alteration of tight junction proteins such as zonula occludens (ZO)-1 and Occludin was evaluated by Western blotting and immunofluorescence staining. Apoptotic change of intestinal mucosa was detected by TUNEL staining and DNA fragmentation ELISA. In vitro, apoptosis-inducing effect of pancreatitis-associated ascitic fluid (PAAF) was examined using T84 cells. Integrity of monolayer cells was assessed by transepithelial electric resistance (TEER).

RESULTS

Permeability of ileum was significantly increased 6 h after induction of SAP. Blood endotoxin level was significantly elevated and bacterial translocation occurred 18 h after induction of SAP. Six hours after induction of SAP, expressions of ZO-1 and Occludin were not altered, but apoptosis of ileum mucosa was significantly accelerated. Addition of PAAF to T84 cells did not affect expressions of ZO-1 or Occludin, but significantly increased the apoptosis and significantly decreased TEER.

CONCLUSIONS

These results suggest that breakdown of intestinal mucosa via accelerated apoptosis may increase in intestinal permeability in SAP and that PAAF contains factor(s) that accelerates the apoptosis of intestinal epithelial cells.

The probiotic bacterium Lactobacillus plantarum species 299 reduces intestinal permeability in experimental biliary obstruction

AIMS

Extrahepatic biliary obstruction is associated with the failure of intestinal barrier function, allowing bacteria and other substances from the intestine to enter the circulation and initiate a systemic inflammatory response, causing impairment of organ function. Probiotic bacteria have been shown to have beneficial effects on intestinal barrier function in other conditions, but their effects have never been studied in biliary obstruction.

METHODS AND RESULTS

This study examined the effects of enteral administration of Lactobacillus plantarum species 299 (LP299) in oatmeal fibre compared with sterile oatmeal fibre in water or water alone in an animal model of biliary obstruction. Administration of LP299 was associated with reduced intestinal permeability compared with sterile oatmeal alone (0.262 +/- 0.105%vs 0.537 +/- 0.037%, P=0.019, percentage excretion of (14)Carbon), but there was no evidence of reduced endotoxin exposure or blunting of the systemic inflammatory response. Animals receiving sterile oatmeal fibre alone also failed to develop the hyperpermeability after biliary obstruction seen in animals receiving water only (0.512+/- 0.05%vs 0.788 +/- 0.18%), suggesting that oatmeal itself may have some beneficial effects on intestinal barrier function.

CONCLUSION

Enteral administration of the probiotic bacterium LP299 reduces intestinal hyperpermeability associated with experimental biliary obstruction.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides insight to direct further work into the modulation of intestinal barrier function by probiotic bacteria.

Glutamine improves intestinal barrier function in experimental biliary obstruction

OBJECTIVE

To determine the effects of enteral administration of glutamine on intestinal barrier function in experimental biliary obstruction.

BACKGROUND

Extrahepatic biliary obstruction is associated with the failure of intestinal barrier function, allowing bacteria and other substances from the intestine to enter the circulation and initiate a systemic inflammatory response, causing impairment of multiple organs. The amino acid glutamine has been shown to improve intestinal barrier function in other conditions, but its effects in biliary obstruction have not been fully examined.

METHODS

This study examined the effects of enteral administration of glutamine on intestinal permeability and on bacterial translocation from the intestine in a rodent model of biliary obstruction.

RESULTS

Glutamine was shown to reduce intestinal permeability measured as percentage excretion of 14C 7 days after biliary obstruction (0.35+/-0.03 vs. 0.56+/-0.085% in controls, p=0.028), and glutamine administration was also associated with a decreased incidence of bacterial translocation to extra-intestinal sites (p=0.03). Radiolabelled bacterial studies also demonstrated reduced translocation of bacterial fragments to extra-intestinal sites in glutamine-treated animals (p=0.01). There was also some evidence of decreased exposure to endotoxin, reduced systemic inflammation and increased bacterial killing by the immune system in glutamine-treated animals.

CONCLUSIONS

Glutamine modulates intestinal permeability and reduces bacterial translocation in an animal model of experimental biliary obstruction and may increase bacterial killing by the immune system.

Gut luminal microdialysis of glycerol as a marker of intestinal ischemic injury and recovery

OBJECTIVE

To evaluate microdialysis as a method to assess different degrees of intestinal damage and recovery during ischemia and reperfusion; to evaluate information obtained from microdialysis catheters in the peritoneum, the gut wall, and the gut lumen.

DESIGN

Randomized, controlled animal experiment.

SETTING

University laboratory animal center.

SUBJECTS

Twenty-seven domestic pigs.

INTERVENTIONS

The superior mesenteric artery was cross-clamped for 60 mins (n = 14) or 120 mins (n = 10) followed by 2 or 4 hrs of reperfusion. Three pigs served as controls.

MEASUREMENTS AND MAIN RESULTS

Intestinal mucosal integrity was assessed by morphometry, adenosine triphosphate in the gut wall, and permeability of C-polyethylene glycol. Lactate, glycerol, pyruvate, and glucose were measured by microdialysis. Changes in adenosine triphosphate, permeability, or lactate did not correlate to different extents of intestinal damage caused by 60 or 120 mins of ischemia. During the reperfusion period, pigs with 60 mins of intestinal ischemia showed a faster recovery of these variables than pigs with 120 mins of intestinal ischemia. Glycerol increased with increasing duration of the ischemic insult. After 60 mins of intestinal ischemia, glycerol in the gut lumen decreased toward baseline but remained high after 120 mins of intestinal ischemia. There was a good correlation between gut luminal glycerol and recovery of mucosal damage throughout the reperfusion period. In the peritoneal cavity, both glycerol and lactate decreased to baseline relatively shortly after onset of reperfusion independent of the duration of intestinal ischemia.

CONCLUSIONS

Microdialysis of glycerol provides information about the extent and severity of intestinal damage after ischemia and about the ensuing recovery. The gut lumen is to be preferred as a site for placement of microdialysis catheters.

Influence of portal blood on the development of systemic inflammation associated with experimental acute pancreatitis

BACKGROUND

The liver is a source of systemic proinflammatory mediators in acute pancreatitis. We have investigated the effects of blood from the pancreas and intestine in liver activation and lung inflammation during early stages of experimental acute pancreatitis in a rat model.

METHODS

A portosystemic shunt and a mesosystemic shunt were created to prevent the passage of blood coming from the pancreas and the intestine, respectively, to the liver. Pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. After 3 hours, the inflammatory process in the lung and intestine, plasma levels of tumor necrosis factor (TNF)-alpha and their soluble receptor, and mRNA expression of inflammatory mediators in the lung were evaluated.

RESULTS

Portocaval shunting of blood prevented the inflammatory process in the lung, an increase in plasma TNF-alpha concentration, and the expression of TNF-alpha, interleukin (IL)-1beta, and heat-shock protein (HSP)-72 in the lung, but had no effect on plasma levels of soluble TNF-alpha receptor or on expression of inducible nitric oxide synthase (iNOS) and macrophage inflammatory protein (MIP)-2 in the lung. In contrast, mesocaval shunting of blood did not modify any of the parameters evaluated.

CONCLUSIONS

Pancreatic blood, but not intestinal blood, plays a key role in liver activation during experimental acute pancreatitis.

A study of intestinal permeability in relation to the inflammatory response and plasma endocab IgM levels in patients with acute pancreatitis

BACKGROUND

There is scarce information regarding intestinal permeability (IP) in patients with acute pancreatitis (AP) and its relationship with systemic inflammatory response and bacterial translocation (BT).

AIMS

To study IP in patients with mild and severe forms of AP as compared with controls and the presumed correlations between IP, the inflammatory response, and endotoxin.

PATIENTS AND METHODS

Sixty-eight patients with AP and 13 healthy controls were included. IP was assessed by means of the lactulose/mannitol (L/M) test, at admission (LMR1), and at the 15th day (LMR2). The presence of endotoxin was assessed by means of endotoxin-core antibodies type IgM (EndoCab IgM), at admission and 15 days later in patients with severe AP. Plasma levels of interleukins 6, 8, 10, and tumor necrosis factor alpha were tested within the first 72 hours from the onset of pain.

RESULTS

Both LMR1 and LMR2 were significantly higher in patients than in controls, and in patients with severe versus mild forms of AP. Plasma levels of Endocab IgM increased significantly in patients with severe AP. Basal plasma levels of pro- and anti-inflammatory cytokines were significantly higher in patients with severe AP. A significant correlation was found between LMR2 and Endocab IgM levels in patients with severe AP (r = 0.73, P = 0.02).

CONCLUSIONS

Patients with AP show an increased IP when compared with controls, being more relevant and persistent in severe cases. This seems related to an increase of endotoxemia late in the course of the disease, but not with an exacerbation of the systemic immune response.

Intestinal injury after thoracic aortic cross-clamping in the pig

BACKGROUND

The mucosal surface epithelium is an essential part of the functional intestinal barrier, but its structural response to ischemia/reperfusion is only partly characterized. The purpose of this study was to provide a detailed morphological evaluation of intestinal surface epithelium after aortic cross-clamping.

MATERIAL AND METHODS

Pigs were subjected to thoracic aortic cross-clamping for 60 min and subsequent reperfusion for 120 min. Tissue blood flow and high-energy phosphates were measured with microspheres and HPLC, respectively. Urinary excretion of (14)C polyethylene glycol (MW 4000 Da) (PEG-4000), loaded into an intestinal loop, provided an index of intestinal permeability.

RESULTS

Jejunal blood flow was restored at 10 min after aortic declamping. Denudation of the basement membrane of the intestinal villi tips, as a consequence of epithelial shedding, increased markedly during the initial 60 min of reperfusion (P = 0.002). During the following 45 min, the denuded basement membrane was partly covered with low cuboidal and squamous-shaped cells extending lamellipodia over a wavy basement membrane. Restoration of ATP at 60 min after aortic declamping correlated inversely to the extent of denuded basement membrane (r = 0.75, P = 0.032). Permeability of PEG-4000 increased markedly after aortic declamping and was linearly correlated to the area of denuded basement membrane (r = 0.87, P = 0.01).

CONCLUSIONS

Reperfusion for 2 h after aortic cross-clamping is associated with initial aggravation of ischemia-induced injury in the porcine jejunum, but thereafter with restitution of the surface epithelium. Restoration of ATP may be important to avoid intestinal injury after ischemia. Increased permeability of a macromolecule in response to reperfusion is closely correlated to injury of the surface epithelium.

The effect of combination therapy of hyperbaric oxygen, meropenem, and selective nitric oxide synthase inhibitor in experimental acute pancreatitis

Despite the new diagnostic and therapeutic advancements, acute pancreatitis has still high rate of morbidity and mortality. We aimed to evaluate the effects of hyperbaric oxygen (HBO) therapy alone or combined with S-methylisothiourea (SMT), and meropenem (MER) therapy in an experimental rat model of acute necrotizing pancreatitis. Rats were randomly divided into 8 groups, and acute pancreatitis was induced in all groups except group 1. Treatment protocols were saline for group 2, SMT for group 3, SMT + MER for group 4, SMT + HBO for group 5, HBO for group 6, HBO + MER for group 7, and MER for group 8. All surviving animals were killed 48 hours after the induction of pancreatitis, and specimens were collected. Oxidative stress parameters, histopathologic scores and amylase levels were better in treatment groups than in the positive control group (group 2). The most favorable results were obtained in HBO treatment groups, especially in HBO + MER group (group 7). Our results indicate that adding HBO therapy to the antibiotic therapy will decrease oxidative stress parameters, serum amylase levels, and histopathological score. We suggest that adding the HBO therapy as an adjunctive to the treatment protocol of acute necrotizing pancreatitis may yield improvement in the morbidity and mortality of the disease.

The role of inducible nitric oxide synthase inhibitor, meropenem, and taurine in experimental acute necrotizing pancreatitis

INTRODUCTION

Translocation of bacteria from the gut is one of the most important factors in the development of septic complications and mortality in acute pancreatitis.

AIMS

To investigate whether S-methylisothiourea (SMT), taurine (TAU), and meropenem (MER) could effect bacterial translocation and the course of acute necrotizing pancreatitis.

METHODOLOGY

Seventy male Sprague-Dawley rats were studied. Rats were randomly allocated into seven groups. Acute pancreatitis was induced in group II (MER), group III (TAU), group IV (TAU + MER), group V (TAU + SMT), group VI (TAU + MER + SMT), and group VII (positive control) by retrograde injection of taurocholate into the common biliopancreatic duct. Group I rats (sham) received normal saline infusion into the common biliopancreatic duct as negative control. Rats were treated with drug combinations intraperitoneally for 48 hours after induction of pancreatitis. At the 48th hour of induction, all animals were killed, and specimens were collected.

RESULTS

Bacterial translocation to peritoneum and pancreas in groups treated with MER were lower than in the other groups. Pancreatic tissue GSHpx and SOD levels were higher in all groups in comparison with levels in group VII. Pancreatic tissue MDA levels were also lower in all treatment groups except group II. The most favorable results were obtained in group VI (TAU + MER + SMT). Also, the lowest pathologic score between the groups in which acute pancreatitis developed was obtained in group VI.

CONCLUSIONS

Addition of TAU and SMT to the treatment protocol for acute pancreatitis seems to improve the pathologic score and oxidative stress parameters. Also, antibiotherapy with MER decreases the risk of bacterial translocation.

Effect of chronic administration of tacrolimus and cyclosporine on human gastrointestinal permeability

The antirejection drug tacrolimus (FK506) has been reported to impair intestinal permeability in an early stage after orthotopic liver transplantation (OLT), and cyclosporine (CsA) has shown a similar effect in animals. We studied the chronic effect of FK506 and CsA on gastroduodenal and intestinal permeability and on blood endotoxin levels in patients 2 to 3 years after OLT. Thirty-two OLT patients (22 men and 10 women; mean age, 44.8 +/- 7.1) who had received CsA (n = 19) or FK506 (n = 13) and 10 healthy volunteers (6 male and 4 female, mean age 41.7 +/- 5.4) were assessed for gastroduodenal permeability by recovery in urine of sucrose after oral administration and for intestinal permeability by recovery in urine after oral loads of rhamnose and lactulose, which evaluate the intracellular and paracellular routes, respectively. In all subjects, plasma levels of endotoxins also were assessed. Gastroduodenal permeability was similar in patients and controls (0.03 +/- 0.003 versus 0.04 +/- 0.01%, P = NS). In regard to intestinal permeability, passage through the intracellular route was significantly reduced in OLT patients compared with controls (1.13 +/- 0.06 versus 2.74 +/- 0.17%, P <.01), but paracellular permeability was unchanged (0.14 +/- 0.007 versus 0.13 +/- 0.01%, P = NS). Serum endotoxin levels were similar in all subjects. We conclude that chronic administration of FK506 or CsA induces a clinically irrelevant, selective dysfunction of monosaccharide absorption, but does not affect gastroduodenal or intestinal permeability.

Gastric colonisation, intestinal permeability and septic morbidity in acute pancreatitis

INTRODUCTION

Bacterial translocation (BT) may represent an important cause of septic morbidity in patients with acute pancreatitis. We have previously demonstrated an association between BT, septic morbidity and colonisation of the proximal GI tract. Alterations in intestinal permeability (IP) may also predispose to BT. The aim of this study was to assess the extent of gastric colonisation, measure IP in patients with acute pancreatitis and relate these to both disease severity and septic complications.

METHODS

Gastric colonisation was determined by culturing a sample of nasogastric aspirate, and IP was measured using a dual sugar probe technique (lactulose/rhamnose test). Disease severity was assessed according to the modified Glasgow (Imrie) criteria. All septic complications were recorded prospectively.

RESULTS

A total of 59 patients were studied (M:F ratio 32:27, median age 66 years, range 18-89), 24 (31%) of whom had severe disease. A nasogastric aspirate was obtained in 56 patients. There was a significantly higher incidence of colonisation with potentially pathogenic enteric bacteria in patients with severe disease compared to those with mild disease (57 vs. 6%, p < 0.001). Septic morbidity occurred in 29% of severe patients and 11% mild patients (p = 0.17). 33% of patients colonised with enteric organisms developed sepsis, compared to 16% with no enteric bacteria in the NG aspirate (p = 0.34). Enteric bacteria caused 77% of the septic complications. Intestinal permeability was neither associated with disease severity nor was it predictive of septic morbidity.

CONCLUSIONS

There is significantly higher incidence of gastric colonisation with enteric bacteria in patients with severe acute pancreatitis, but no difference in IP. Enteric bacteria were implicated in the majority of septic complications. These findings support the gut origin of sepsis hypothesis in acute pancreatitis.

The gut origin of bacterial pancreatic infection during acute experimental pancreatitis in rats

BACKGROUND

Infections are frequent complications and determine clinical course and outcome in severe pancreatitis. A novel animal model was used to assess minimal transit time of bacterial translocation (BT) across the gut mucosa in vivo using green fluorescent protein-transfected Escherichia coli and intravital video microscopy.

METHODS

Three hours after induction of acute pancreatitis by i.p. injection of 40 microg/kg cerulein, 0.5 ml of a suspension of green fluorescent protein-transfected E. coli were injected into the lumen of a small bowel reservoir formed by ligature in anesthetized Wistar rats. Translocation of E. coli was assessed by intravital microscopy. Animals were sacrificed 5 h after induction of pancreatitis.

RESULTS

BT across the mucosa and into the muscularis propria took a mean +/- SD of 36.4 +/- 8 min and 80.9 +/- 9.5 min, respectively, in sham animals. Pancreatitis resulted in a significantly shorter minimal transit time across the mucosa (16.4 +/- 4.9 min, p = 0.007) and into the muscularis propria (47.7 +/- 2.5 min, p = 0.001). E. coli were detected on frozen cross-sections and on bacteriological examination of pancreatic tissue in animals with acute pancreatitis but not in controls.

DISCUSSION

Intravital microscopy of fluorescent bacteria is a new approach towards studying BT in vivo. Minimal transit time of BT serves as a novel functional aspect of mucosal barrier function during acute pancreatitis. The observation of fluorescent bacteria translocating from the small bowel lumen into the pancreas provides substantial experimental proof for the gut-origin-hypothesis of infectious complications in pancreatitis.

Role of the gut in the course of severe acute pancreatitis

INTRODUCTION

The pathogenesis of acute pancreatitis remains elusive. Sepsis and multiple organ failure continue to cause death (overall mortality rate, approximately 10%) despite immense improvements in supportive, radiologic, and surgical therapy. The gut appears to play a key role in the development of these complications.

AIM

To critically review the evidence implicating the gut in the pathogenesis of acute pancreatitis.

METHODS

Relevant English-language literature or abstracts cited in the MEDLINE database were reviewed.

RESULTS AND CONCLUSION

Gram-negative enteric organisms account for most infections of pancreatic necrosis and subsequent sepsis, which suggests the gut as a source. Intestinal permeability is increased early in patients with severe acute pancreatitis and correlates with endotoxemia, which suggests translocation as a possible mechanism. The pathogenesis of the deranged function of the gut mucosal barrier and the possible sites of increase in intestinal permeability are discussed. The gut also plays a role in priming neutrophils and the release of inflammatory cytokines, which initiate and propagate nearly all the detrimental consequences of severe inflammation and sepsis. Future research avenues and potential therapeutic measures that may restore and preserve gut barrier function are explored.

The role of the intestine in the pathophysiology and management of severe acute pancreatitis

BACKGROUND

The outcome of severe acute pancreatitis has scarcely improved in 10 years. Further impact will require new paradigms in pathophysiology and treatment. There is accumulating evidence to support the concept that the intestine has a key role in the pathophysiology of severe acute pancreatitis which goes beyond the notion of secondary pancreatic infection. Intestinal ischaemia and reperfusion and barrier failure are implicated in the development of multiple organ failure.

DISCUSSION

Conventional management of severe acute pancreatitis has tended to ignore the intestine. More recent attempts to rectify this problem have included 1) resuscitation aimed at restoring intestinal blood flow through the use of appropriate fluids and splanchnic-sparing vasoconstrictors or inotropes; 2) enteral nutrition to help maintain the integrity of the intestinal barrier; 3) selective gut decontamination and prophylactic antibiotics to reduce bacterial translocation and secondary infection. Novel therapies are being developed to limit intestinal injury, and these include antioxidants and anti-cytokine agents. This paper focuses on the role of the intestine in the pathogenesis of severe acute pancreatitis and reviews the implications for management.

Enteral versus parenteral nutrition for acute pancreatitis

BACKGROUND

Acute pancreatitis creates a catabolic stress state promoting a systemic inflammatory response and nutritional deterioration. Adequate supply of nutrients plays an important role to ensure optimum recovery. Total parenteral nutrition (TPN) has been the standard practice for providing exogenous nutrients to patients with severe acute pancreatitis. However, recent data suggest that enteral nutrition (EN) is feasible. Thus, a comparison of EN and TPN in patients with acute pancreatitis needs to be made.

OBJECTIVES

To compare the effect of total parenteral nutrition (TPN) versus enteral nutrition (EN) on mortality, morbidity and length of hospital stay in patient with acute pancreatitis.

SEARCH STRATEGY

Trials were identified by computerized searches of The Cochrane Controlled Trials Register, MEDLINE, and EMBASE. Additional studies were identified and included where relevant by searching Scisearch, the bibliographies of review articles and identified trials, and personal files. The search was undertaken in August, 2000 and updated in September 2002. No language restrictions were applied.

SELECTION CRITERIA

Randomized clinical trials, in which nutrition support with TPN were compared to EN in patients with acute pancreatitis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. Information was collected on death, length of hospital stay, systemic infection, local septic complications, and other local complications.

MAIN RESULTS

Two trials with a total of 70 participants were included. The relative risk (RR) for death with EN vs TPN was 0.56 (95% CI 0.05 to 5.62). Mean length of hospital stay was reduced with EN (WMD -2.20, 95% CI -3.62 to -0.78). RR for systemic infection with EN vs TPN was 0.61 (95% CI 0.29 to 1.28). In one trial, RR for local septic complications and other local complications with EN vs TPN was 0.56 (95% CI 0.12 to 2.68) and 0.16 (95% CI 0.01 to 2.86) respectively.

REVIEWER'S CONCLUSIONS

Although there is a trend towards reductions in the adverse outcomes of acute pancreatitis after administration of EN, clearly there are insufficient data to draw firm conclusions about the effectiveness and safety of EN versus TPN. Further trials are required with sufficient size to account for clinical heterogeneity and to measure all relevant outcomes.

The early increase in intestinal permeability and systemic endotoxin exposure in patients with severe acute pancreatitis is not associated with systemic bacterial translocation: molecular investigation of microbial DNA in the blood

INTRODUCTION

Sepsis is the main cause of late mortality in patients with severe acute pancreatitis and is largely attributed to secondary infection of pancreatic necrosis with gram-negative enteric organisms. This is commonly preceded by a significant increase in intestinal colonization with such microbes and with early increases in intestinal permeability, thus suggesting a mechanism of bacterial translocation. Whilst cultures of blood specimens from these patients often remain sterile, it is conceivable that bacteria might translocate in small volumes with detrimental effects but elude detection by standard microbial culture techniques.

AIMS

To investigate the incidence and frequency with which bacterial DNA may exist in the systemic circulation of patients with acute pancreatitis and to relate that to disease severity, changes in intestinal permeability, and systemic endotoxin exposure.

METHODOLOGY

Blood samples were obtained at admission and on days 3 and 7 from 26 patients with acute pancreatitis (seven with severe cases) and from 10 healthy controls for DNA extraction and standard microbial cultures. Polymerase chain reaction techniques were used to amplify a gene region (16S ribosomal RNA) found in all bacteria. Levels of serum endotoxin and antibodies to endotoxin core (EndoCAb) were measured at admission, and intestinal permeability to the macromolecule polyethylene glycol 3350 was determined within 72 hours of the onset of symptoms.

RESULTS

Blood cultures yielded and enterococci for one patient with a severe attack and coagulase-negative staphylococci for another patient with a mild attack. No bacterial DNA was found in any of the samples. Endotoxemia was detected in 20 patients (five with severe cases), and levels of serum IgM EndoCAb were depleted in patients with severe attacks but remained relatively unchanged during mild attacks (p = 0.033). Intestinal permeability was significantly increased in patients with severe attacks of acute pancreatitis but remained unchanged during mild attacks (p < 0.05).

CONCLUSIONS

Whilst severe attacks of acute pancreatitis are associated with early derangement in gut barrier function and systemic endotoxin translocation, there is no molecular evidence for associated bacterial "translocation."

Nutrition support during acute pancreatitis

Studies have shown that protein catabolism increases by 80% and energy expenditure by 20% in acute pancreatitis, indicating that nutritional requirements are elevated. Other studies have associated the resolution of negative nitrogen balance by nutrition support with improved outcome. Consequently, the need for effective nutrition is one cornerstone of management of acute pancreatitis. Concerns that feeding may exacerbate the disease process by stimulating the synthesis of proteolytic enzymes in the acinar cell and perpetuating autolysis has led to the widespread use of total parenteral nutrition (TPN) and bowel rest. Unfortunately, the use of TPN in clinical practice has been associated with major metabolic and infective complications, possibly because 1). patients with acute pancreatitis are intolerant of glucose due to coexistent pancreatic endocrine dysfunction and 2). the disease causes immune suppression. This has led to the search for alternatives. Based on physiologic studies, infusion of nutrients into the distal jejunum bypasses the stimulatory effect of feeding on pancreatic secretion. Many controlled trials have compared TPN with jejunal feeding. No study has shown that jejunal feeding exacerbates the disease. Further, jejunal feeding is associated with fewer infectious and metabolic complications. These observations and the fact that enteral feeding is one-tenth the cost of TPN has resulted in the general acceptance of jejunal feeding as the preferred mode for maintaining nutrition in patients with acute pancreatitis.

Intestinal permeation and gastrointestinal disease

The gastrointestinal tract constitutes one of the largest sites of exposure to the outside environment. The function of the gastrointestinal tract in monitoring and sealing the host interior from intruders is called the gut barrier. A variety of specific and nonspecific mechanisms are in operation to establish the host barrier; these include luminal mechanisms and digestive enzymes, the epithelial cells together with tight junctions in between them, and the gut immune system. Disruptions in the gut barrier follow injury from various causes including nonsteroidal anti-inflammatory drugs and oxidant stress, and involve mechanisms such as adenosine triphosphate depletion and damage to epithelial cell cytoskeletons that regulate tight junctions. Ample evidence links gut barrier dysfunction to multiorgan system failure in sepsis and immune dysregulation. Additionally, contribution of gut barrier dysfunction to gastrointestinal disease is an evolving concept and is the focus of this review. An overview of the evidence for the role of gut barrier dysfunction in disorders such as Crohn's disease, celiac disease, food allergy, acute pancreatitis, non-alcoholic fatty liver disease, and alcoholic liver disease is provided, together with critical insight into the implications of this evidence as a primary disease mechanism.