Serosal but not mucosal endotoxin exposure increases intestinal permeability in vitro in the rat

Rheumatologic Associations of Microscopic Colitis: A Narrative Review

Extra-intestinal manifestations are frequent complications of the classical inflammatory bowel diseases, Crohn's disease and ulcerative colitis. However, in addition to the classical diseases, there is a spectrum of conditions, often termed "microscopic colitis", in which extra-intestinal manifestations are less well described. Our objective was to review the literature regarding the extra-intestinal manifestations complicating microscopic colitis and describe the association with systemic autoimmune rheumatic diseases. A comprehensive search and review of peer-reviewed English-language and international journals and reports was completed based on key terms, including "microscopic colitis", "lymphocytic colitis", "collagenous colitis", "inflammatory bowel disease", "extraintestinal manifestations", and the specific disease associations utilizing the PubMed Central database and MEDLINE. A broad spectrum of rheumatologic manifestations has been reported in patients with microscopic colitis. The identification of rheumatoid arthritis and limited scleroderma as co-morbidities with microscopic colitis was noteworthy. Inflammatory arthropathy was frequently seen in microscopic colitis, usually preceding or occurring in conjunction with the onset of gastrointestinal symptoms. A variety of presentations of associated arthritis were reported: migratory, symmetric or asymmetric, peripheral or axial, oligoarticular or polyarticular, erosive or non-erosive. There was a high incidence of autoantibodies in these patients, supporting a potential autoimmune association. On the basis of these anecdotal reports, we would suggest development of a clinical registry to help define the incidence of extra-intestinal manifestations and systemic autoimmune rheumatic diseases among microscopic colitis patients to help elucidate shared predispositions, pathogenic mechanisms and therapeutic opportunities.

Lipopolysaccharides in Food, Food Supplements, and Probiotics: Should We be Worried?

The fever-inducing effect of lipopolysaccharides (LPS) is well known, and human blood is extremely responsive to this pyrogen. Recently, the safety of LPS-containing food supplements and probiotic drugs as immune-stimulants has been questioned, although these products are orally taken and do not reach the bloodstream undigested. The concerns are understandable, as endotoxaemia is a pathological condition, but the oral uptake of probiotic products containing LPS or Gram-negative bacteria does not pose a health risk, based on the available scientific evidence, as is reviewed here. The available methods developed to detect LPS and other pyrogens are mostly used for quality control of parentally applied therapeuticals. Their outcome varies considerably when applied to food supplements, as demonstrated in a simple comparative experiment. Products containing different Escherichia coli strains can result in vastly different results on their LPS content, depending on the method of testing. This is an inherent complication to pyrogen testing, which hampers the communication that the LPS content of food supplements is not a safety concern.

A mouse model of shigellosis by intraperitoneal infection

In human and nonhuman primates, Shigella spp. cause bacillary dysentery by invading colon epithelium and promoting a strong inflammatory response; however, adult mice are resistant to oral Shigella infection. In this study, intraperitoneal challenge with virulent S. flexneri 2a (YSH6000) resulted in diarrhea and severe body weight loss in adult B6 mice. Of note, virulent S. flexneri 2a could invade and colonize not only systemic tissues but also the serosa and lamina propria region of the large intestine. In addition, epithelial shedding, barrier integrity, and goblet cell hyperplasia were found in the large intestine by 24 hours post-intraperitoneal Shigella infection. Of note, predominant expression of proinflammatory cytokines and chemokines were found in the large intestine after intraperitoneal challenge. Monocytes played a critical role in attenuating diarrhea and in providing protective efficacy against intraperitoneal Shigella infection. Most importantly, mice prevaccinated with attenuated S. flexneri 2a (SC602) strain were protected against intraperitoneal challenge with YSH6000. When taken together, these findings show that intraperitoneal challenge with virulent S. flexneri 2a can provoke bacillary dysentery and severe pathogenesis in adult mice. This model may be helpful for understanding the induction mechanism of bacillary dysentery and for evaluating Shigella vaccine candidates.

Tumor necrosis factor alpha increases intestinal permeability in mice with fulminant hepatic failure

AIM: To determine the effect of tumor necrosis factor alpha (TNF-α) on intestinal permeability (IP) in mice with fulminant hepatic failure (FHF), and the expression of tight junction proteins.

METHODS: We selected D-lactate as an index of IP, induced FHF using D-galactosamine/lipopolysaccharide and D-galactosamine/TNF-α, assessed the results using an enzymatic-spectrophotometric method, transmission electron microscopy, immunohistochemistry, Western blotting and real-time quantitative polymerase chain reaction. The effect of the administration of anti-TNF-α immunoglobulin G (IgG) antibody, before the administration of D-galactosamine/lipopolysaccharide, on TNF-α was also assessed.

RESULTS: IP was significantly increased in the mouse model of FHF 6 h after injection (13.57 ± 1.70 mg/L, 13.02 ± 1.97 mg/L vs 3.76 ± 0.67 mg/L, P = 0.001). Electron microscopic analysis revealed tight junction (TJ) disruptions, epithelial cell swelling, and atrophy of intestinal villi. Expression of occludin and claudin-1 mRNA was significantly decreased in both FHF models (occludin: 0.57 ± 0.159 fold vs baseline, P = 0.000; claudin-1: 0.3067 ± 0.1291 fold vs baseline, P = 0.003), as were the distribution density of proteins in the intestinal mucosa and the levels of occludin and claudin-1 protein (occludin: 0.61 ± 0.0473 fold vs baseline, P = 0.000; claudin-1: 0.6633 ± 0.0328 fold vs baseline, P = 0.000). Prophylactic treatment with anti-TNF-α IgG antibody prevented changes in IP (4.50 ± 0.97 mg/L vs 3.76 ± 0.67 mg/L, P = 0.791), intestinal tissue ultrastructure, and the mRNA levels of occludin and claudin-1 expression (occludin: 0.8865 ± 0.0274 fold vs baseline, P = 0.505; claudin-1: 0.85 ± 0.1437 fold vs baseline, P = 0.1), and in the protein levels (occludin: 0.9467 ± 0.0285 fold vs baseline, P > 0.05; claudin-1: 0.9533 ± 0.0186 fold vs baseline, P = 0.148).

CONCLUSION: Increased in IP stemmed from the downregulation of the TJ proteins occludin and claudin-1, and destruction of the TJ in the colon, which were induced by TNF-α in FHF mice.

Elevated lipopolysaccharide in the colon evokes intestinal inflammation, aggravated in immune modulator-impaired mice

Frequency of gram-negative bacteria is markedly enhanced in inflamed gut, leading to augmented LPS in the intestine. Although LPS in the intestine is considered harmless and, rather, provides protective effects against epithelial injury, it has been suggested that LPS causes intestinal inflammation, such as necrotizing enterocolitis. Therefore, direct effects of LPS in the intestine remain to be studied. In this study, we examine the effect of LPS in the colon of mice instilled with LPS by rectal enema. We found that augmented LPS on the luminal side of the colon elicited inflammation in the small intestine remotely, not in the colon; this inflammation was characterized by body weight loss, increased fluid secretion, enhanced inflammatory cytokine production, and epithelial damage. In contrast to the inflamed small intestine induced by colonic LPS, the colonic epithelium did not exhibit histological tissue damage or inflammatory lesions, although intracolonic LPS treatment elicited inflammatory cytokine gene expression in the colon tissues. Moreover, we found that intracolonic LPS treatment substantially decreased the frequency of immune-suppressive regulatory T cells (CD4(+)/CD25(+) and CD4(+)/Foxp3(+)). We were intrigued to find that LPS-promoted intestinal inflammation is exacerbated in immune modulator-impaired IL-10(-/-) and Rag-1(-/-) mice. In conclusion, our results provide evidence that elevated LPS in the colon is able to cause intestinal inflammation and, therefore, suggest a physiological explanation for the importance of maintaining the balance between gram-negative and gram-positive bacteria in the intestine to maintain homeostasis in the gut.

Effect of in vitro exposure to Vibrio vulnificus on hydroelectrolytic transport and structural changes of sea bream (Sparus aurata L.) intestine

The everted gut sac technique has been used to investigate the effect of Vibrio vulnificus on water and electrolyte (Na(+), K(+), Cl(-), HCO(3)(-)) transport on the intestine of sea bream (Sparus aurata L.). Both the anterior and the posterior intestine were incubated in a medium containing 10(8) V. vulnificus cells ml(-1) at 25 degrees C for 2 h. The presence of V. vulnificus resulted in a significant reduction (P < 0.05) of water absorption in the anterior intestine, while sodium absorption in the anterior (P < 0.01) and posterior (P < 0.05) intestine was elevated. Chloride absorption was increased, but the changed was not significant, while potassium absorption decreased significantly (P < 0.05), but only in the posterior intestine. Incubation the sea bream intestine with V. vulnificus did not affect carbonate secretion in the anterior segment, whereas high secretion was stimulated in the posterior segment (P < 0.01). Histological evaluations demonstrated damage in the anterior intestine of sea bream that was characterized by the detachment of degenerative enterocytes, alterations in the microvilli, and the presence of a heterogenous cell population, indicating inflammation. Based on our results, we conclude that V. vulnificus caused cell damage to the intestine of sea bream and that the anterior intestine is more susceptible than the posterior part of the intestine. Several hypotheses are suggested to explain our observations, such as the presence of higher numbers of villosities in the anterior intestine than in the posterior one and/or the presence of endogenous bacteria in the posterior intestine which may have a protector role.

The involvement of Aeromonas salmonicida virulence factors in bacterial translocation across the rainbow trout, Oncorhynchus mykiss (Walbaum), intestine

The pathogenic bacterium Aeromonas salmonicida is the causative agent of furunculosis, a lethal disease in salmonids. The mode of lateral transmission has not been conclusively defined, but A. salmonicida is able to translocate across the intestinal epithelium of salmonids, making the intestinal route a probable candidate. This study investigated some of the virulence mechanisms used by the bacteria to promote translocation. Intestinal segments were placed in modified Ussing chambers to investigate epithelial functions during exposure to bacterial factors. The factors were: extracellular products (ECP), lipopolysaccharide (LPS) or live or heat-inactivated A. salmonicida. Fluorescein isothiocynate (FITC)-labelling enabled detection of translocated bacteria by fluorometry. Live A. salmonicida translocated to a greater degree than heat-inactivated bacteria, suggesting that the bacteria utilize a heat sensitive surface-bound virulence factor which promotes translocation. The epithelium was negatively affected by ECP, manifested as decreased net ion transport, indicating a disturbance in ion channels or cell metabolism. LPS did not affect the epithelium in vitro when administered on the luminal side of the intestinal segment, but significantly increased epithelial translocation of fluorescent bacterial-sized microspheres when administered on the serosal side. This is suggested to be caused by increased transcellular transport, as the paracellular permeability was unaffected indicating maintained epithelial integrity.

Effect of Lactobacillus plantarum enteral feeding on the gut permeability and septic complications in the patients with acute pancreatitis

OBJECTIVE

To study the effect of the Lactobacillus plantarum (LP) enteral feeding on the gut permeability and sepsis in the patients with acute pancreatitis.

SUBJECTS

Seventy-six subjects who stayed over 1 week in the hospital completed the study. Subjects were not treated with any lactobacillus supplement before the intervention.

METHODS

Seventy-six patients with acute pancreatitis were randomly divided into two groups, parenteral nutrition (PN) group (n=38) and ecoimmunonutrition (EIN) group supplied by LP enteral feeding (n=36). The acute physiology and chronic health evaluation score, Balthazar CT score, CRP, fecal bacterial species and DNA fingerprint profiles as well as the potentially pathologenic organisms in nasogastric aspirate were determined on the day of admission and on the 8 day. The intestinal permeability was assessed by measurement of the ratio of lactulose/rhamnose on the day of admission and on days 5 and 8. The rate of organ failure, septic complications and death cases were evaluated at the 8 day.

RESULTS

Following 7 days treatment, 38.9% patients in the EIN group were colonized with multiple organisms compared to 73.7% in the PN group (P<0.01), and 30.6% patients in the EIN grew potentially pathogenic organisms compared to 50% patients in PN group (P<0.05). The fecal bacterial DNA fingerprint profiles were less, the amount of lactobacteria and bifidobacteria decreased, and the amount of enterococci increased in PN group as compared with EIN group, P<0.05. By day 8, the lactulose/rhamnose ratio in EIN group were lower than that in PN group at days 5 and 8, P<0.05. The patients with LP got a better clinical outcomes as compared with the patients with PN.

CONCLUSION

EIN enteral feeding can attenuate disease severity, improve the intestinal permeability and clinical outcomes.

Human oviductal stromal fibroblasts, but not oviductal epithelial cells, express Toll-like receptor 4: the site-specific mucosal immunity of the human fallopian tube against bacterial infection

PROBLEM

To evaluate the site-specific immunoregulatory mechanisms against bacterial infection in the human fallopian tubes.

METHOD OF STUDY

We investigated the effects of lipopolysaccharide (LPS) on the production of CXC chemokines by cultured oviductal epithelial cells (OEC) and oviductal stromal fibroblasts (OSF). The expression of Toll-like receptor (TLR) 4 and CD14 protein in OEC and OSF were evaluated. The phosphorylation of the inhibitor kappaB-alpha (IkappaB-alpha) protein after LPS stimulation was also examined.

RESULTS

Lipopolysaccharide stimulated the secretion of granulocyte chemotactic protein-2, growth-regulated oncogene-alpha, and epithelial neutrophil activating peptide-78 by OSF, but not by OEC. The phosphorylation of the IkappaB-alpha protein was not detected in OEC after stimulation by LPS, whereas IkappaB-alpha phosphorylation was observed in OSF after stimulation by LPS. The expression of the TLR4 protein and mRNA was detected only in OSF but not in OEC. The expression of CD14 was not detected in either OEC or OSF.

CONCLUSION

These results suggest that epithelial cells and fibroblasts in the human fallopian tube have evolved a unique, site-specific mechanism for recognizing Gram-negative pathogens. The lack of TLR4 in OEC may be important for avoiding a state of unnecessary inflammation that could disrupt the epithelial barrier and cause irreversible tubal scarring.

High-fat enteral nutrition reduces endotoxin, tumor necrosis factor-alpha and gut permeability in bile duct-ligated rats subjected to hemorrhagic shock

BACKGROUND/AIMS

Cholestatic patients are prone to septic complications after major surgery due to an increased susceptibility to endotoxin and hypotension. High-fat enteral nutrition reduces endotoxin after hemorrhagic shock. However, it is unknown whether this nutritional intervention is protective in biliary obstruction. We investigated the effect of high-fat enteral nutrition on endotoxin, tumor necrosis factor-alpha (TNF-alpha) and intestinal permeability in cholestatic rats subjected to hemorrhagic shock.

METHODS

Bile duct-ligated (BDL) rats were fasted or fed with low-fat or high-fat enteral nutrition before hemorrhagic shock. Blood and tissue samples were taken after 90 min.

RESULTS

Plasma endotoxin decreased after hemorrhagic shock in BDL-rats fed with high-fat nutrition compared to fasted (P<0.01) and low-fat treated rats (P<0.05). Additionally, circulating TNF-alpha was reduced in BDL-rats pretreated with high-fat nutrition compared to fasted rats (P<0.01). The increased intestinal permeability to macromolecules was reduced by high-fat enteral nutrition, whereas bacterial translocation did not significantly change. Simultaneously, tight junction distribution in ileum and colon was disrupted in non-treated BDL-rats but remained unchanged in high-fat pretreated BDL-rats.

CONCLUSIONS

High-fat enteral nutrition protects against endotoxin-mediated complications independently of intraluminal bile. These results provide a potential new strategy to prevent endotoxin-mediated complications in cholestatic patients undergoing major surgery.

Comparison of two Chinese medical herbs, Huangbai and Qianniuzi, on influence of short circuit current across the rat intestinal epithelia

Huangbai (Phellodendron spec.) and Qianniuzi (Pharbitis spec.) are two traditional Chinese medical herbs used for anti-diarrheal and laxative agents, respectively. Ethanol and water extracts of these two herbs were prepared and effects of the extracts on ion transport of the rat intestinal epithelia were studied. For measuring changes of the short circuit current across the epithelia, the rat intestinal epithelia were mounted in the Ussing chamber and attached with voltage/current clamp. The intestinal epithelia were firstly activated by serosal administration of 5 microM forskolin. As current raised and being stable, extracts of these herbs were added, respectively, and changes in the short circuit current were recorded. Ethanol extract of Huangbai attenuated the current increment; on the contrary, ethanol extract of Qianniuzi augmented the current increment additionally. Water extracts of the two herbs showed minor effects on the current in comparison to ethanol extracts. The results provide evidences to reveal the pharmacological mechanism of the two Chinese medical herbs on the intestinal tissue.

Differential effect of immune cells on non-pathogenic Gram-negative bacteria-induced nuclear factor-kappaB activation and pro-inflammatory gene expression in intestinal epithelial cells

We have previously shown that non-pathogenic Gram negative bacteria induce RelA phosphorylation, nuclear factor (NF)-kappaB transcriptional activity and pro-inflammatory gene expression in intestinal epithelial cells (IEC) in vivo and in vitro. In this study, we investigated the molecular mechanism of immune-epithelial cell cross-talk on Gram-negative enteric bacteria-induced NF-kappaB signalling and pro-inflammatory gene expression in IEC using HT-29/MTX as well as CaCO-2 transwell cultures Interestingly, while differentiated HT-29/MTX cells are unresponsive to non-pathogenic Gram negative bacterial stimulation, interleukin-8 (IL-8) mRNA accumulation is strongly induced in Escherichia coli- but not Bacteroides vulgatus-stimulated IEC cocultured with peripheral blood (PBMC) and lamina propria mononuclear cells (LPMC). The presence of PBMC triggered both E. coli- and B. vulgatus-induced mRNA expression of the Toll-like receptor-4 accessory protein MD-2 as well as endogenous IkappaBalpha phosphorylation, demonstrating similar capabilities of these bacteria to induce proximal NF-kappaB signalling. However, B. vulgatus failed to trigger IkappaBalpha degradation and NF-kappaB transcriptional activity in the presence of PBMC. Interestingly, B. vulgatus- and E. coli-derived lipopolysaccharide-induced similar IL-8 mRNA expression in epithelial cells after basolateral stimulation of HT-29/PBMC cocultures. Although luminal enteric bacteria have adjuvant and antigenic properties in chronic intestinal inflammation, PBMC from patients with active ulcerative colitis and Crohn's disease differentially trigger epithelial cell activation in response to E. coli and E. coli-derived LPS. In conclusion, this study provides evidence for a differential regulation of non-pathogenic Gram-negative bacteria-induced NF-kappaB signalling and IL-8 gene expression in IEC cocultured with immune cells and suggests the presence of mechanisms that assure hyporesponsiveness of the intestinal epithelium to certain commensally enteric bacteria.

Pretreatment With High-Fat Enteral Nutrition Reduces Endotoxin and Tumor Necrosis Factor-?? and Preserves Gut Barrier Function Early After Hemorrhagic Shock

Gram-negative sepsis is a potentially fatal clinical syndrome characterized by a proinflammatory response (tumor necrosis factor-alpha) to bacterial (endo)toxins and gut barrier function loss. Recently, we found that high-fat enteral nutrition protects against late bacterial translocation in a model of hemorrhagic shock in rats. However, the basis for this protection is unknown. We hypothesized that the observed protection is the result of an early inhibition of endotoxin and the subsequent inflammatory response resulting in a preserved gut barrier function. Sprague-Dawley rats were divided into a group that was starved overnight (HS-S), fed with a low-fat enteral diet (HS-LF) or fed wih a high-fat enteral diet (HS-HF), and subsequently subjected to a nonlethal hemorrhagic shock. Ninety minutes after hemorrhage, arterial endotoxin significantly decreased in HS-HF rats (4.0 +/- 0.6 pg/mL) compared with HS-LF rats (10.7 +/- 0.9 pg/mL, P = 0.002) and HS-S rats (15.2 +/- 2.2 pg/mL P = 0.001). Interestingly, arterial tumor necrosis factor-alpha was also decreased in HS-HF rats (17.9 +/- 10.4 pg/mL) compared with HS-LF (83.5 +/- 16.7 pg/mL, P < 0.01) and HS-S rats (180.9 +/- 67.9 pg/mL, P < 0.02). Loss of tight junction structure (ZO-1) observed in ileum and colon of control hemorrhagic shock rats was prevented in HS-HF rats. In parallel, intestinal barrier function was preserved in HS-HF rats, evidenced by a reduced permeability to horseradish peroxidase (P < 0.05), less bacterial invasion, and a 10-fold reduction of bacterial translocation early after hemorrhagic shock. This report describes a new strategy to nutritionally prevent endotoxemia, the subsequent inflammatory response and gut barrier failure following hemorrhagic shock. High-fat enteral nutrition requires further evaluation as an intervention to prevent a potentially fatal systemic inflammatory response in patients at risk for sepsis.

Effect of Ethanol Extracts of Three Chinese Medicinal Plants with Laxative Properties on Ion Transport of the Rat Intestinal Epithelia

The effects of ethanol extracts of three Chinese medicinal plants Dahuang (Rheum palmatum L.), Badou (Croton tiglium L.), and Huomaren (Cannabis sativa L.), on ion transport of the rat intestinal epithelia were studied. Rat intestinal epithelia mounted in an Ussing chamber attached with voltage/current clamp were used for measuring changes of the short-circuit current across the epithelia. The intestinal epithelia were activated with current raised by serosal administration of forskolin 5 microM. Ethanol extracts of the three plants all augmented the current additively when each was added after forskolin. In subsequent experiments, ouabain and bumetanide were added prior to ethanol extracts of these medicinal plants to determine their effect on Na(+) and Cl(-) movement. The results suggest that ethanol extracts of the three medicinal plants may affect the Cl(-) movement more directly than Na(+) movement in the intestinal epithelial cells. The results provide evidence for the pharmacologic mechanism of the three Chinese medicinal plants on the intestinal tract.

Effect of Ethanol Extracts of Three Chinese Medicinal Plants With Anti-diarrheal Properties on Ion Transport of the Rat Intestinal Epithelia

Effects of ethanol extracts of three Chinese medicinal plants, namely, Qinpi (Fraxini cortex), Kushen (Sophora flavescens, AITON), and Huanglian (Coptis teeta, WALLICH), on ion transport of the rat intestinal epithelia were determined in this study. Rat intestinal epithelia mounted in an Ussing chamber attached to a voltage/current clamp were used for measuring changes in the short circuit current across the epithelia. Activation of the intestinal epithelia by serosal administration of 5 microM forskolin resulted in an increase in basal short circuit current. The ethanol extracts of each of the three plants partially reduced the current stimulated by forskolin. In the following experiments, ouabain and bumetanide were added prior to adding the ethanol extract of these plants for revealing their effect on Na(+) and Cl(-) movement. The results suggest that the ethanol extract of the Qinpi would affect Cl(-) transport. On the contrary, the ethanol extract of Kushen would affect Na(+) transport rather than Cl(-) movement. This study provides evidences that reveal the pharmacological mechanism of the Chinese plants with anti-diarrheal properties.

Effects of radiation damage on intestinal morphology

The current flow of papers on intestinal structure, radiation science, and intestinal radiation response is reflected in the contents of this review. Multiparameter findings and changes in compartments, cells, or subcellular structure all contribute to the overall profile of the response. The well-recognized changes in proliferation, vessels, and fibrogenesis are accompanied by alterations in other compartments, such as neuroendocrine or immune components of the intestinal wall. The responses at the molecular level, such as in levels of hormones, cytokines, or neurotransmitters, are of fundamental importance. The intestine responds to localized radiation, or to changes in other organs that influence its structure or function: some structural parameters respond differently to different radiation schedules. Apart from radiation conditions, factors affecting the outcome include the pathophysiology of the irradiated subject and accompanying treatment or intervention. More progress in understanding the overall responses is expected in the next few years.

Beneficial effects of growth hormone on bacterial translocation during the course of acute necrotizing pancreatitis in rats

Because bacterial translocation from the gut is one of the important sources of bacterial infection in acute necrotizing pancreatitis (ANP) and growth hormone (GH) has the ability to promote the intestinal epithelial proliferation, we investigated the effects of GH on bacterial translocation in a rat ANP model. ANP was induced in rats by injection of 5% sodium taurocholate into the biliopancreatic duct. The rats with ANP were treated with either human recombinant GH or placebo. Laparotomized animals without induction of ANP (sham operation [SO]) served as controls. At 24 hours after operation, blood was drawn for bacterial culture and determination of amylase, lipase, and endotoxin. Peritoneal fluid and specimens of mesenteric lymph nodes (MLN), liver, pancreas, and spleen were taken for bacterial culture by standard techniques. Intestinal mucosal permeability was assessed by measuring the movement of 125I-labeled albumin from blood to intestinal lumen. Insulin-like growth factor-1 (IGF-1) mRNA was detected in the liver and ileum by reverse transcriptase-polymerase chain reaction (RT-PCR). Morphologic changes of pancreas and ileum were also analyzed. Administration of GH significantly decreased the serum amylase, lipase activities, plasma endotoxin level, and incidence of bacterial translocation. Moreover, the survival rate of ANP rats was improved. The severity of inflammation in pancreas and ileum was alleviated by GH treatment. Ileal mucosal thickness, villus height, and crypt depth in GH treatment rats were obviously increased compared with those of ANP rats. The intestinal permeability was markedly improved in the GH group versus the ANP group. GH treatment resulted in up-regulation of IGF-1 mRNA expression in ileum, but not in liver. These results suggested that exogenous GH had beneficial effects in maintaining the integrity of intestinal mucosal barrier and reducing the incidence of bacterial translocation in rats with ANP. One of the mechanisms might be the up-regulation of IGF-1 mRNA in intestine by GH treatment.

Gut mucosal injury is attenuated by recombinant bactericidal/permeability-increasing protein in hind limb ischemia-reperfusion injury

Lower limb ischemia-reperfusion injury (IRI) is associated with increased gut permeability to endotoxin, which not only directly damages enterocytes but also stimulates a systemic inflammatory response syndrome (SIRS), compounding gut injury. Recombinant bactericidal/permeability-increasing protein (rBPI21) is a novel anti-endotoxin therapy with proven benefit in sepsis. Its potential role in modulating remote gut injury in hind limb IRI was studied. Male Wistar rats were chosen for a prospective randomized control trial (n = 10 per group). The control group and two groups undergoing 3 hr bilateral hind limb ischemia with 2 hr reperfusion (I/R) were randomized to receive intravenously either control protein thaumatin at 2 mg/kg or rBPI21 at 2 mg/kg, respectively. Quantitative morphometric assessment of the small bowel was used as a measure of gut injury and, using an ex vivo everted gut sac model, translocation of 14C-labeled polyethylene glycol (PEG) was used as a measure of gut permeability. Our results indicate that hind limb IRI is associated with remote gut mucosal injury and increased permeability to macromolecules. rBPI21 anti-endotoxin therapy modulates remote gut injury associated with lower limb IRI in this model.

Small intestinal permeability

The noninvasive assessment of small intestinal permeability in humans is now within the capability of any routine biochemistry laboratory. There remain however, many pitfalls for the unwary when performing these tests. Importantly, it has now been shown that normal intestinal permeability relates to geographical location rather than race. Recent studies show that it may be possible to simplify the procedure even further. The main recent focus of interest in measuring intestinal permeability relates to patients with AIDS and inflammatory bowel disease, the effects of nonsteroidal anti-inflammatory drugs on the small bowel, and the use of these tests in the pediatric population and critically ill. Some groups have now started to focus their attention on the possible systemic consequences of increased intestinal permeability, whereas others have shown that increased small bowel permeability results in small intestinal inflammation that may in turn be associated with blood and protein loss.