Severe Mucosal Damage Research Articles

Serology in adults with celiac disease: limited accuracy in patients with mild histological lesions

Celiac disease (CD) is a gluten-triggered enteropathy, presenting with insidious clinical patterns. It can occasionally be diagnosed in asymptomatic subjects. Our aim was to define the relationship among symptoms at diagnosis, serological markers [tissue transglutaminase antibodies (tTGA), anti-endomysium antibodies (EMA) anti-actin antibodies (AAA)] and degree of mucosal damage. A total of 68 consecutive adult patients with CD were enrolled. Intestinal biopsies were scored according to the Marsh classification modified by Oberhuber: I-II minimal lesions or absent villous atrophy; IIIA partial villous atrophy; IIIB-C total villous atrophy (TVA). HLA-typing was done for all patients. No association between clinical presentation and severity of mucosal damage was found. Presence of EMA or tTGA was significantly associated with more severe mucosal damage (P < 0.001). Of 12 patients, 11 with AAA were also positive for TVA. The severity of mucosal damage is the main factor governing the detectability of serological markers of CD. The sensitivity of serological testing is questionable in patients with minimal lesions.

The Effect of Nicorandil on Small Intestinal Ischemia–Reperfusion Injury in a Canine Model

It has been shown that nicorandil, which has both ATP-sensitive K+ (KATP) channel opener-like and nitrate-like properties, has an organ-protective effect in ischemia-reperfusion injury in several experimental animal models. We evaluate the effectiveness of nicorandil on warm ischemia-reperfusion injury of the small intestine in a canine model. Eighteen beagle dogs were divided into three groups: the control group (n=6); the nicorandil group (n=6), to which nicorandil was injected intravenously before the ischemia; and the glibenclamide group (n=6), to which glibenclamide, which closes the KATP channel and does not suppress the nitrate effect of nicorandil, was orally administered, and then nicorandil was injected in the same manner as in the nicorandil group. Both the superior mesenteric artery and vein were clamped for 2 h. Superior mesenteric artery blood flow, small intestinal mucosal tissue blood flow, intramucosal pH, and histopathological analyses were compared among the three groups. Superior mesenteric artery blood flow, mucosal tissue blood flow and pHi after reperfusion were significantly maintained in the nicorandil in comparison with the control and the glibenclamide groups. The histopathological findings showed less severe mucosal damage after reperfusion in the nicorandil group compared with the other two groups. Between the control group and the glibenclamide group, no significant differences were observed in all those parameters. This study suggests that nicorandil has a protective effect on small intestinal IR injury, and activation of KATP channels plays an important role in inhibiting small intestinal IR injury.

Prolonged Intestinal Mucosal Barium Coating due to Ischemic Necrosis

A case of a 63-year-old man with small bowel ischemia six weeks after transplantation surgery is presented. Plain abdominal radiograph obtained several days after ingestion of barium shows the sign of prolonged barium coating indicating severe mucosal damage. Abdominal CT scan demonstrates small bowel wall thickening as well as pockets of peritoneal fluid collections. Most critically, CT allows visualization of subtle traces of dense barium within the dependent portions of this fluid indicating bowel perforation.

Celiac disease in children and adolescents at a singe center in Saudi Arabia

BACKGROUND AND OBJECTIVES:Celiac disease (CD) is an immune-mediated enteropathy, induced by gluten in genetically susceptible individuals. The objective of this study was to describe the clinical pattern of CD in children from the western region of Saudi Arabia.DESIGN AND SETTING:Retrospective, hospital-based.PATIENTS AND METHODS:This study included children with a biopsy-proven diagnosis of CD made between September 2002 and July 2007. Children were admitted to the endoscopy unit for a small-bowel biopsy if they had gastrointestinal symptoms suggestive of CD or if they were positive for a CD-antibody screen performed for the high-risk groups.RESULTS:Eighty children were identified with a diagnosis of CD. Their mean (SD) age was 9.6 (4.9) years (range, 0.5-18 years). There were 44 (55%) female patients. Forty-one (51%) patients were detected during screening of high-risk groups, while 39 (49%) patients had classical symptoms of malabsorption. The screening also detected asymptomatic patients. Of 65 patients tested, 11 (17%) had elevated liver function tests, which reverted to normal after introduction of a gluten-free diet (GFD) except in one case. Seventy-three (91%) patients were positive for anti-tissue transglutaminase antibodies, 18 (23%), for IgG anti-gliadin antibodies; and 46 (58%), for IgA anti-gliadin antibodies. Forty-one (56%) patients showed good adherence to GFD as assessed by dietary history and the decline in anti-tTG level.CONCLUSION:CD may present with classical symptoms or be identified through screening programs. Growth and laboratory abnormalities usually improve after introduction of a GFD. Adherence to a GFD remains a problem; therefore, thorough assessment and counseling at the time of diagnosis and ongoing care are crucial.

Ketamine reduces intestinal injury and inflammatory cell infiltration after ischemia/reperfusion in rats

Intestinal ischemia reperfusion (I/R) induces severe injury and significant mortality. New therapeutic interventions are needed; ketamine is an anesthetic with anti-inflammatory properties, which has shown protective effects on I/R in various organs. This study investigated effects of ketamine on intestinal I/R injury. Male Wistar rats underwent either sham surgery or 30 min of intestinal ischemia followed by 60 min reperfusion. Ketamine pretreatment was administered by intraperitoneal injections at doses of 100, 50, 12.5, or 6.25 mg/kg. The intestinal morphology, mucosal damage, leukocyte infiltration, serum P-selectin, serum intracellular adhesion molecule-1 (ICAM-1), serum antithrombin-III (ATIII), and myenteric ganglion cell structure were evaluated. Intestinal I/R led to severe mucosal damage, leukocyte (especially neutrophil) infiltration, P-selectin and ICAM-1 elevations, ATIII depletion, and myenteric ganglion cell morphological alterations. The ketamine dose dependently diminished these alterations (except for ICAM-1 serum levels), reaching statistical significance at 100, 50, and 12.5 mg/kg. Ketamine protects the intestine against I/R injury. Ketamine anesthesia has been recommended for clinical situations of sepsis and hemodynamic instability, both frequent during intestinal I/R. The clinical application of ketamine in situations of intestinal I/R warrants consideration.

IgA anti-actin antibodies in celiac disease

The purpose of this study was to determine the sensitivity and specificity of IgA anti-actin antibodies (IgA-AAA) for celiac disease (CD), to investigate their usefulness as a marker of compliance in CD patients to the gluten-free diet (GFD), and to assess the relationship between their presence in the sera of CD patients and severity of intestinal mucosal damage. A total of 182 patients with CD were studied: 63 patients were untreated; 50 patients were following a strict GFD; and 69 patients were non-compliant with a GFD. IgA-AAA was detected using a homemade enzyme-linked immunosorbent assay (ELISA). IgA-AAA showed a sensitivity of 41.3% and a specificity of 71.4% for a diagnosis of CD. In children, the frequency of IgA-AAA detection was lower in those following a strict GFD (23.1%) compared with untreated patients (39.4%) and those not complying with a GFD (32.5%). In patients following a strict GFD, IgA-AAA detection was significantly less frequent in children than in adults (23.1% vs. 58.3%, respectively; P<0.001). IgA-AAA was found in 17 out of 52 CD patients with total villous atrophy (32.7%), and in one out of 11 patients with subtotal villous atrophy (9%). IgA-AAA cannot replace anti-endomysium and anti-tissue transglutaminase antibodies in the diagnosis algorithm of CD, but it can serve as a reliable marker of severe intestinal mucosal damage in CD patients.

Failure of liver function tests in predicting drug clearance of chemotherapeutic agents in a patient who had recovered from hepatic congestion

Failure of liver function tests in predicting drug clearance of chemotherapeutic agents in a patient who had recovered from hepatic congestion

IgA anti-Actin antibodies in children with celiac disease: comparison of immunofluorescence with Elisa assay in predicting severe intestinal damage

BackgroundPrevious studies have demonstrated that the presence of serum IgA antibodies against actin filaments (AAA) in patients with celiac disease (CD) is strongly associated with mucosal damage and severe degrees of villous atrophy.The aims of the present study were (1) to verify the effectiveness of IgA-AAA in newly diagnosed CD patients in a clinical setting (2) to compare the immunofluorescence assay with ELISA assay; (3) to compare the correlation of our IgA anti-tissue transglutaminase antibodies (tTG-Ab) class with mucosal intestinal lesions.Methods90 patients underwent endoscopy and multiple biopsies for suspected CD on the basis of symptoms, in presence of positive tTG-Ab tests. Twenty biopsied and 25 not-biopsied subjects with negative tTG-Ab were tested as control groups.IgA-AAA assays were performed by indirect immunofluorescence using rat epithelial intestinal cells, and by ELISA with a commercial kit. tTG-Ab assay was a radio-binding assay.Intestinal specimens were collected by upper endoscopy and the histological study was done according to the Marsh's classification modified by Oberhuber (M/O). Auto-antibodies assays and histological evaluation have been performed blindly by skilled operators.ResultsCD diagnosis was confirmed in 82 patients (type I M/O in 2 patients, IIIA in 18 patients, IIIB in 29 patients and IIIC in 33 patients). Two patients with type 1 lesion in presence of positive tTG-Ab and abdominal complaints, started a gluten free diet.The rate of IgA-AAA positivity (sensitivity) by IFI and ELISA in histologically proven celiac disease patients, were 5.5% and 25% patients in IIIA, 27.5% and 34.4% patients in IIIB, 78.8% and 75% in IIIC patients, respectively.Patients with normal or nearly normal mucosa, regardless of tTG-Ab status, presented negative IgA-AAA IFI assay. On the other hand, 1 patient with normal mucosa but positive tTG-Ab, also presented positive IgA-AAA ELISA. All healthy non biopsied controls had negative IgA-AAA. tTG-Ab serum concentration was significantly correlated with more severe intestinal lesion (IIIB, IIIC M/O).ConclusionsIgA-AAA may be undetectable in presence of severe mucosal damage. Histology is still necessary to diagnose celiac disease and IgA-AAA cannot be included in usual screening tests, because it has little to offer if compared to the well-established tTG-Ab.IgA-AAA could be an adjunctive, very useful tool to support the diagnosis of CD in case of suboptimal histology, when the biopsy is to be avoided for clinical reasons, or in case of negative parents' consensus.

A piglet model of acute gastroenteritis induced by Shigella dysenteriae Type 1.

The lack of a standardized laboratory animal model that mimics key aspects of human shigellosis remains a major obstacle to addressing questions about pathogenesis, screening therapeutics, and evaluation of vaccines. We characterized a piglet model for Shigella dysenteriae type 1. Piglets developed acute diarrhea, anorexia, and dehydration, which could often be fatal, with symptom severity depending on age and dose. Bacteria were apparent in the lumen and on the surface epithelium throughout the gut initially, but severe mucosal damage and bacterial cellular invasion were most profound in the colon. Detached necrotic colonocytes were present in the lumen, with inflammatory cells outpouring from damaged mucosa. High levels of interleukin (IL)-8 and IL-12 were followed by high levels of other proinflammatory cytokines. Elevated levels of tumor necrosis factor-alpha, IL-1beta, IL-6, and IL-10 were detected in feces and in gut segments from infected animals. Bacteria were present inside epithelial cells and within colonic lamina propria. In contrast, an isogenic strain lacking Shiga toxin induced similar but milder symptoms, with moderate mucosal damage and lower cytokine levels. We conclude that piglets are highly susceptible to shigellosis, providing a useful tool with which to compare vaccine candidates for immunogenicity, reactogenicity, and response to challenge; investigate the role of virulence factors; and test the efficacy of microbial agents.

Histological and Ultrastructural Study of the Stomach Mucosa of Adult Male Albino Rats after Horizontal Gastroplasty and Cimetidine Administration

Background: The severity of mucosal damage after horizontal gastroplasty is closely related to the high PH of the pouch. Cimetidine proved to promote healing of acute gastric erosions. Aim of the Work: This research was carried out to investigate the effect of horizontal gastroplasty on the stomach mucosa and protective effect of cimetidine. Materials and Methods: A total of 15 male adult rats were divided into three equal groups. The first one considered as control. The second group was exposed to horizontal gastroplasty. The third group was exposed to horizontal gastroplasty with immediate injection of Cimetidine in a dose of 200 mg/kg/ daily for one month. The rats were sacrificed after the last dose of the drug and the stomach was removed and different sections were prepared for light and electron microscopic investigation. Results: Examination of the gastric mucosa in the control group revealed the traditional mucosal architecture. In the second group using L/M examination, the different types of cells of gastric glands were distorted with condensation of their nuclei and disruption of the epithelium of gastric glands. There was a focal area of inflammation with marked increase of inflammatory cells and areas of congestion. The lumens of gastric glands were markedly dilated and the connective tissue between the glands was increased. By E/M examination, some nuclei appeared small and condensed .The cell membrane surrounded the cells disappeared, the Golgi apparatus was dilated, the mitochondria were swelled with distortion of their cristae and the rER were distended with shedding of their ribosomes. The microvilli disappeared and secretory granules were scanty with small clear and irregular vacuoles. In the third group, L/M and E/M examinations revealed that most affections appeared in the second group have vanished.

Relationship between gastro‐oesophageal reflux pattern and severity of mucosal damage

The aim of the study is to compare the characteristics of reflux episodes in controls and in patients with various degrees of oesophagitis and Barrett's oesophagus. Ambulatory 24-h impedance-pH tracings were analysed from healthy volunteers, patients with non-erosive reflux disease (NERD), patients with grade A oesophagitis, grade B oesophagitis, grade C or D oesophagitis and patients with a short segment (<2 cm) of Barrett's metaplasia. The number of acid and weakly acidic reflux episodes increased from 25.9 +/- 3.9 to 17.9 +/- 1.5 in the controls, 39.9 +/- 6.3 to 33.4 +/- 5.7 in the patients with NERD, 46.6 +/- 6.2 to 40.4 +/- 9.2 in grade A, 68.2 +/- 9.2 to 49.2 +/- 12.3 in grade B, 79.8 +/- 15.6 to 47.4 +/- 4.6 in grade C/D and 75.1 +/- 7.9 to 37.3 +/- 8.5 in the patients with Barrett. The proportion of reflux episodes that is acidic or alkaline was similar all groups. Comparison with normal values revealed that none of the controls, 40% of the patients with NERD, 50% of the patients with grade A, 80% of the patients with grade B and all patients with grade C/D or Barrett's oesophagus had an abnormally high total number of reflux episodes. In the patients with severe oesophagitis a significantly higher percentage of reflux episodes reached the proximal oesophagus (43.8%) compared to the patients with Barrett's oesophagus (19.2%). With increasing degrees of oesophagitis, patients have more reflux episodes but a large overlap between the groups exists making comparison with normal values of limited relevance. In patients with Barrett's oesophagus fewer reflux episodes reach the proximal oesophagus which might explain their low sensitivity to reflux.

546 Relationship Between Gastroesophageal Reflux Pattern and Severity of Mucosal Damage

546 Relationship Between Gastroesophageal Reflux Pattern and Severity of Mucosal Damage

547 A Study On the Intercellular Space of Squamous Epithelium in Lower-Esophagus with Light Microscopy in the Diagnosis of GERD

(between 53.0 and 66.4%) or alkaline (between 0.5 and 1.3%) was similar in all groups. However, the median nadir pH of reflux episodes decreased with increasing severity of mucosal damage and was highest in the controls (pH 3.8) and lowest in the patients with Barrett (pH 2.5). Besides an increased number of reflux episodes, the acid clearance time of the acid reflux episodes was significantly longer in the patients with severe esophagitis (134±20 s) and Barrett's esophagus (104±21 s) compared to the controls (58±30 s), patients with NERD (73±14 s), LA A (84±49 s) and LA B (70±35 s). Comparison with normal values revealed that none of the controls, 40% of the patients with NERD, 50% of the patients with LA A, 80% of the patients with LA B and all patients with LA C/D or Barrett's esophagus had an abnormally high total number of reflux episodes. In the patients with severe esophagitis a significantly higher percentage of reflux episodes reached the proximal esophagus (43.8%) compared to the patients with Barrett's esophagus (19.2%). Conclusions: Not only the number of acid reflux episodes but also the number of weakly acidic reflux episodes is increased in patients with increasing severity esophagitis and Barrett's esophagus. However, a large overlap between the groups exists which implies that comparison to normal values is of limited relevance. In patients with Barrett's esophagus fewer reflux episodes reach the (more sensitive) proximal esophagus which might explain their low sensitivity to reflux.

Follow-up of adult celiac patients: which noninvasive test reflects mucosal status most reliably?

SPECIFIC AUTHOR CONTRIBUTIONS: Andreas Vécsei, MD, and Ulrike Graf wrote the manuscript. All authors contributed to study design, data collection and analysis, and approved the final draft for submission. The corresponding author declares that the manuscript is submitted on behalf of all authors. The best mode of follow-up in celiac disease has not yet been established. The intention of this study was to clarify which noninvasive follow-up investigation - serological tests or intestinal permeability test (IPT) - correlates best with histology and whether the interval between diagnosis and follow-up affects the accuracy of these tests. Data from adult patients with celiac disease (diagnosed between December 1989 and July 2006) followed up with biopsy, IPT, and serological tests [IgG anti-gliadin antibodies (AGA-IgG), AGA-IgA, and endomysial antibodies (EMA)] were retrieved from a computerized database. Results of noninvasive tests were compared with the persistence of villous atrophy on biopsy. Patients were divided into groups A, which comprised patients followed up within 2 years after diagnosis, and B, comprising patients followed up later than 2 years. Forty-seven patients were evaluable. The lactulose/mannitol (L/M) ratio had a sensitivity of 85 % and a specificity of 46.2 % for mucosal atrophy, whereas saccharose excretion showed a sensitivity of 60 % and a specificity of 52.6 %. The sensitivities of AGA-IgA and AGA-IgG were 15 % and 20 %, respectively, while specificity was 100 % for both. Validity of AGA was limited due to low number of positive results. EMA assay was 50 % sensitive and 77.8 % specific. In group A (n = 23) L/M ratio performed best in terms of sensitivity (88.9 %), whereas EMA achieved a higher specificity (71.4 %). In group B, the sensitivity of the L/M ratio decreased to 85.7 %, while the specificity of EMA increased to 91.7 %. In this study, none of the noninvasive tests was an accurate substitute for follow-up biopsy in detecting severe mucosal damage.

Mycobacterium avium paratuberculosisInvades Human Small‐Intestinal Goblet Cells and Elicits Inflammation

Crohn disease is a chronic inflammatory bowel disease of unknown etiology. Mycobacterium avium paratuberculosis (MAP) was found in the gut of patients with Crohn disease, but causality was not established. Fully developed, germ-free human small intestine and colon were established by subcutaneous transplantation of fetal gut into SCID (severe combined immunodeficiency) mice thereafter infected by direct intraluminal inoculation of MAP. We have found that MAP actively invades the human gut epithelial goblet cells of the small intestine, inducing severe tissue damage and inflammation. These observations indicate that MAP can specifically colonize the normal human small intestine and can elicit inflammation and severe mucosal damage.

Evaluation of Brushing Cytology in the Diagnosis of Helicobacter pylori Gastritis

To evaluate clinical utility of rapid urease test (RUT), brash cytology and histology for detecting Helicobacter pylori.Brush cytology materials were obtained from the antrum of the stomach in 109 patients who suffered from dyspepsia and were candidates for endoscopy. RUT and histology with hematoxylin-eosin staining were performed. Infection status was established by observation of typical HP in cytology or biopsy.A total of 78% ofpatients were diagnosed as positivefor HP organisms using brush cytology; 66% had histologic results positive for HP and 59% for RUT. Observation of typical organism by cytology or histology was the gold standard; 3 tests results were compared. Sensitivity of brush cytology (95%) was higher than that of histology (80.5%) and RUT (72%).Gastric brushing cytology provides a sensitive, inexpensive, accurate and easy technique for rapid detection of HP infection. When additional information on severity of mucosal damage or presence of cell atypias is not necessary, histologic examination can be omitted; a cost-effective strategy for assessing HP status might consist of taking antral biopsies, the former for RUT, and performing brush cytology slides, which should be stained and examined only when the RUT result is negative.

EFFECT OF BENCYCLANE FUMARATE ON INTESTINAL ISCHAEMIA REPERFUSION INJURY

Post-ischaemic intestinal tissue damage appears to be due to the formation of oxygen radicals. Free radical-initiated lipid peroxidation following intestinal ischaemia/reperfusion (I/R) may disrupt mucosal integrity. Indirectly, the radicals trigger the accumulation of neutrophils within the affected tissue, initiating inflammatory processes that lead to severe mucosal lesions. We have investigated the protective effect of bencyclane fumarate, a vasodilating Ca(2+) channel blocker, which has been used for the treatment of peripheral arterial occlusive diseases, on intestinal ischaemia reperfusion (IR) injury in rats. Forty-eight Wistar albino rats were divided into three groups: a sham-operated group (no IR injury, n = 16), an ischaemic control group (IR, n = 16), and BF-treated group (pretreatment 5 mg/kg bencyclane fumarate + IR, n = 16). A marker for lipid peroxidation, namely malondialdehyde; free radical scavengers, glutathione peroxidase, catalase and superoxide dismutase levels; an index of polymorphonuclear neutrophils, myeloperoxidase activity and mucosal damage were investigated. Malondialdehyde levels, myeloperoxidase activity and the severity of mucosal damage were decreased in the BF group. In addition, in the BF group, glutathione peroxidase, catalase and superoxide dismutase levels were higher compared with the IR group. The pretreatment of rats with bencyclane fumarate before intestinal ischaemia attenuates the mucosal damage in intestinal IR injury, probably by altering lipid peroxidation, neutrophil accumulation and antioxidant activity.

Noncytotoxic Clostridium perfringens Enterotoxin (CPE) Variants Localize CPE Intestinal Binding and Demonstrate a Relationship between CPE-Induced Cytotoxicity and Enterotoxicity

Clostridium perfringens enterotoxin (CPE) causes the symptoms of a very common food poisoning. To assess whether CPE-induced cytotoxicity is necessary for enterotoxicity, a rabbit ileal loop model was used to compare the in vivo effects of native CPE or recombinant CPE (rCPE), both of which are cytotoxic, with those of the noncytotoxic rCPE variants rCPE D48A and rCPE(168-319). Both CPE and rCPE elicited significant fluid accumulation in rabbit ileal loops, along with severe mucosal damage that starts at villus tips and then progressively affects the entire villus, including necrosis of epithelium and lamina propria, villus blunting and fusion, and transmural edema and hemorrhage. Similar treatment of ileal loops with either of the noncytotoxic rCPE variants produced no visible histologic damage or fluid transport changes. Immunohistochemistry revealed strong CPE or rCPE(168-319) binding to villus tips, which correlated with the abundant presence of claudin-4, a known CPE receptor, in this villus region. These results support (i) cytotoxicity being necessary for CPE-induced enterotoxicity, (ii) the CPE sensitivity of villus tips being at least partially attributable to the abundant presence of receptors in this villus region, and (iii) claudin-4 being an important intestinal receptor for CPE. Finally, rCPE(168-319) was able to partially inhibit CPE-induced histologic damage, suggesting that noncytotoxic rCPE variants might be useful for protecting against some intestinal effects of CPE.

The Novel NF-κB Inhibitor, Dehydroxymethylepoxyquinomicin, Prevents Local and Remote Organ Injury Following Intestinal Ischemia/Reperfusion in Rats

Nuclear factor-kappaB regulates the expression of several genes involved in inflammation, the immune response, apoptosis, cell survival, and proliferation. Many of these same genes are activated during ischemia/reperfusion (I/R) injury. Here, we examined the anti-inflammatory efficacy of a newly developed nuclear factor-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), in the intestinal I/R injury model of rats. Intestinal ischemia was induced by occluding the superior mesenteric artery for 60 min. The experimental animals were divided into two groups: untreated group, control; treated group, DHMEQ-treated (20 mg/kg). DHMEQ were administered intraperitoneally at 60 min prior to clamping and 5 min prior to reperfusion. Animal survival rates, intestinal tissue blood flow, serum levels of tumor necrosis factor-alpha, and interleukin-6, and the histopathology of both the intestine and the lung were analyzed. The DHMEQ-treated animals exhibited higher values of intestinal tissue blood flow and suppression of tumor necrosis factor-alpha and interleukin-6 production, resulting in marked prolongation of their survival times. Histopathological findings obtained by examining tissues from control animals revealed severe intestinal mucosal damage and disruption of the lung alveolar architecture accompanied by hemorrhage and marked neutrophilic infiltration. These findings were significantly ameliorated in DHMEQ-treated animals. DHMEQ effectively prevented both intestine and lung injuries in rat intestinal I/R models. This agent may possess a good potency for clinical application in various pathological settings including intestinal I/R and/or inflammatory acute lung injury.

Expression of TLR-2, TLR-4, NOD2 and pNF-κB in a Neonatal Rat Model of Necrotizing Enterocolitis

BackgroundThe etiology of necrotizing enterocolitis (NEC) results from a combination of several risk factors that act synergistically and occurs in the same circumstances as those which lead to innate immunity activation. Pattern recognition molecules could be an important player in the initiation of an exaggerated inflammatory response leading to intestinal injury in NEC.Methodology/Principal FindingsWe specifically evaluated intestinal epithelial cell (IEC) expression of Toll-like receptor 2 (TLR-2), TLR-4, NOD2 and phosphorylated NF-κB (pNF-κB) after mucosal injury in a rat model of NEC induced by prematurity, systemic hypoxia, and a rich protein formula. In the control group (group 1), neonatal rats were full-term and breast-fed; in the experimental groups, rat pups were preterm at day 21 of gestation and rat-milk fed (group 2) or hand-gavaged with a protein rich formula after a hypoxia–reoxygenation procedure (group 3). Morphological mucosal changes in the small bowel were scored on hematoxylin- and eosin-stained sections. Immunohistochemistry was performed on frozen tissue sections using anti TLR-2 and active pNF-κB p65 antibodies. Real-time RT-PCR was performed to assess mRNA expression of NOD2, TLR-2 and TLR-4. Proliferation and apoptosis were studied in paraffin sections using anti Ki-67 and caspase-3 antibodies, respectively. The combination of immaturity, protein rich formula and a hypoxia–reoxygenation procedure induces pathological mucosal damage consistent with NEC. There was an overexpression of TLR-2, and pNF-κB in IECs that was correlated with the severity of mucosal damage, together with an increase of apoptotic IECs and markedly impaired proliferation. In addition, these immunological alterations appeared before severe mucosal damage. TLR-2 mRNA were also increased in NEC together with TLR-4 mRNA using real-time RT-PCR whereas NOD2 expression was unchanged.Conclusions/SignificanceThese results show that this rat model of NEC induced mucosal injury, leading to a highly responsive IEC phenotype and suggesting that alterations in the innate immune system participates in the pathogenesis of NEC and are enhanced by prematurity.