Reduction of hydrogen sulfide synthesis enzymes cystathionine-ß-synthase and cystathionine-γ-lyase in the colon of patients with Hirschsprungs disease.

PURPOSE: Hirschsprung associated enterocolitis (HAEC) is the most common cause of morbidity and mortality in Hirschsprung Disease (HSCR). The pathogenesis of HAEC is poorly understood. In recent years, there is increasing evidence that a compromised intestinal barrier function plays a major role in the pathogenesis of HAEC. Hydrogen sulfide, synthesized from L-cysteine by two key enzymes, cystathionine-ß-synthase (CBS) and cystathionine-γ-lysase (CSE) is reported to play a key role in regulating gastrointestinal motility and promoting resolution of inflammation. We designed this study to test the hypothesis that CBS and CSE expression is altered in the colon of patients with HSCR. METHODS: We investigated CBS and CSE protein expression in both the aganglionic and ganglionic regions of HSCR patients (n=10) versus healthy control colon (n=10). Protein distribution was assessed by using immunofluorescence and confocal microscopy. Gene and protein expression was quantified using quantitative real-time polymerase chain reaction (qPCR), Western blot analysis, and densitometry. MAIN RESULTS: qPCR and Western blot analysis revealed that CBS and CSE are expressed in the normal human colon. CBS and CSE expression was significantly decreased (p<0.003) in the ganglionic and aganglionic bowel in HSCR compared to controls. Confocal microscopy revealed that CBS and CSE expression in smooth muscles, interstitial cells of Cajal, platelet-derived growth factor-alpha receptor-positive cells, enteric neurons and colonic epithelium was markedly decreased in HSCR specimens compared to controls. CONCLUSION: We demonstrate for the first time the expression and distribution of CBS/CSE in patients with HSCR. The observed decreased expression of CBS and CSE may affect mucosal integrity and colonic contractility and thus render HSCR patients more susceptible to develop HAEC.

Altered tryptophan hydroxylase 2 expression in enteric serotonergic nerves in Hirschsprung's-associated enterocolitis.

AIM: To determine if expression of colonic tryptophan hydroxylase-2 (TPH2), a surrogate marker of neuronal 5-hydroxytryptamine, is altered in Hirschsprung's-associated enterocolitis. METHODS: Entire resected colonic specimens were collected at the time of pull-through operation in children with Hirschsprung's disease (HSCR, n = 12). Five of these patients had a history of pre-operative Hirschsprung's-associated enterocolitis (HAEC). Controls were collected at colostomy closure in children with anorectal malformation (n = 10). The distribution of expression of TPH2 was evaluated using immunofluorescence and confocal microscopy. Protein expression of TPH2 was quantified using western blot analysis in the deep smooth muscle layers. RESULTS: TPH2 was co-expressed in nitrergic and cholinergic ganglia in the myenteric and submucosal plexuses in ganglionic colon in HSCR and healthy controls. Co-expression was also seen in submucosal interstitial cells of Cajal and PDGFRα(+) cells. The density of TPH2 immuno-positive fibers decreased incrementally from ganglionic bowel to transition zone bowel to aganglionic bowel in the myenteric plexus. Expression of TPH2 was reduced in ganglionic bowel in those affected by pre-operative HAEC compared to those without HAEC and healthy controls. However, expression of TPH2 was similar or high compared to controls in the colons of children who had undergone diverting colostomy for medically refractory HAEC. CONCLUSION: Altered TPH2 expression in colonic serotonergic nerves of patients with HSCR complicated by HAEC may contribute to intestinal secretory and motor disturbances, including recurrent HAEC.

[Cyclooxygenase 2 inhibitors and colorectal cancer]. / Inhibiteurs de la cyclo-oxygénase 2 et cancer colorectal.

Cyclooxygenase-2 (Cox2) is an inductible isoenzyme of cyclooxygenase undetectable in normal colonic mucosa and overexpressed in 80% colonic tumor. Several works in vitro and in vivo showed that Cox2 plays a key role in the multistep process of colorectal tumorigenesis such apoptosis inhibition of cellular proliferation and angiogenesis induction. So that Cox2 represent a potential molecular target in colorectal management and specific Cox2 inhibitors may be useful as chemopreventive as well as therapeutic agent in humans. In animals study Cox2 inhibitors was shown to be effective and in humans Cox2 inhibitors are approved by the Food and Drug Administration as an adjunct to endoscopic surveillance and surgery in patients with Familial Adenomatous Polyposis (FAP). The purpose of this article is to review the relationship between Cox2/Cox2 inhibitors and differents signaling pathways of colorectal carcinogenesis and to precise their possible molecular mechanisms of action. This work although review clinicals data of their efficacy as chemopreventive agent as well as therapeutic in the differents group at risk for colorectal cancer.

Abnormalities in liver enzyme levels during Salmonella enteritidis enterocolitis.

OBJECTIVE: To evaluate the prevalence, associated factors, and time-course changes of abnormal liver enzyme serum levels in adult patients with Salmonella enteritidis enterocolitis. METHODS: The clinical records of 104 patients (age range 15-86 years, 46.2% males) admitted to hospital because of S. enteritidis enterocolitis were reviewed. The prevalence of abnormal liver enzyme levels was evaluated, as well as its possible relationship to data of systemic inflammatory response, severe sepsis, and bacteremia. In addition, time-course changes in serum levels of liver enzymes were studied in 16 cases with available follow-up after hospital discharge. RESULTS: In patients without a pre-existing cause for liver enzyme abnormalities (n = 84), the prevalence of serum AST elevation was 23.0% (95% CI 15.4-34.5%), of serum ALT elevation was 17.9% (95% CI 0.6-20.0%), and of GGT elevation was 19.0% (95% CI 11.6-29.3%). The prevalence of abnormality for any of these enzymes (AST, ALT, or GGT) was 35.7% (95% CI 25.7-46.8%). The prevalence of altered serum alkaline phosphatase was lower. Alteration in liver enzyme serum levels was moderate in the majority of cases, and was found in association with the presence of fever. Serum enzyme levels decreased during the convalescence period after hospital discharge. CONCLUSIONS: Abnormalities in liver enzyme levels are frequent during severe enterocolitis due to S. enteritidis in adult patients. These abnormalities are moderate and self-limited.

Reduced oxidative and nitrosative damage in murine experimental colitis in the absence of inducible nitric oxide synthase.

BACKGROUND: Oxidative and nitrosative stress have been implicated in the pathogenesis of inflammatory bowel diseases. AIMS: To study the role of nitric oxide (NO) derived from inducible NO synthase (iNOS) in an experimental model of murine enterocolitis. METHODS: Trinitrobenzene sulphonic acid (TNBS) was instilled per rectum to induce a lethal colitis in iNOS deficient mice and in wild type controls. The distal colon was evaluated for histological evidence of inflammation, iNOS expression and activity, tyrosine nitration and malondialdehyde formation (as indexes of nitrosative and oxidative stress), myeloperoxidase activity (as index of neutrophil infiltration), and tissue localisation of intercellular adhesion molecule 1 (ICAM-1). RESULTS: TNBS administration induced a high mortality and weight loss associated with a severe colonic mucosal erosion and ulceration, increased myeloperoxidase activity, increased concentrations of malondialdehyde, and an intense staining for nitrotyrosine and ICAM-1 in wild type mice. Genetic ablation of iNOS gene conferred to mice a significant resistance to TNBS induced lethality and colonic damage, and notably reduced nitrotyrosine formation and concentrations of malondialdehyde; it did not, however, affect neutrophil infiltration and intestinal ICAM-1 expression in the injured tissue. CONCLUSION: Data show that activation of iNOS is required for nitrosative and oxidative damage in experimental colitis.

Localization and secretion of tissue kallikrein in peptidoglycan-induced enterocolitis in Lewis rats.

The plasma kallikrein-kinin system is a mediator of intestinal inflammation induced by peptidoglycan-polysaccharide from group A streptococci (PG-APS) in rats. In this study we investigated the participation of intestinal tissue kallikrein (ITK). Lewis rats were injected intramurally with PG-APS. ITK was visualized by immunohistochemical staining. Cecal ITK concentration was measured by radioimmunoassay, and gene expression was evaluated by RNase protection assay. Kallikrein-binding protein (KBP) was evaluated in plasma by ELISA. Tissue kallikrein was identified in cecal goblet cells in both control and PG-APS-injected rats and in macrophages forming granulomas in inflamed tissues. Cecal ITK was significantly lower in acute and chronic phases of inflammation and in supernatant from in vitro cultures of inflamed cecum. ITK mRNA levels were not significantly different. Plasma KBP levels were significantly reduced in inflamed rats. The presence of tissue kallikrein in macrophages suggests participation in experimental colitis. The decrease of ITK in the inflamed intestine associated with unchanged mRNA levels suggests ITK release during intestinal inflammation.