Post-surgical recurrence of Crohn's disease: Situational analysis and future prospects.

Surgery retains a major role in the treatment of Crohn's disease, and the prevention of post-operative recurrence is an essential issue. In fact, despite the increasing use of biotherapies, almost all of the patients who undergo surgery will present with a recurrence, initially endoscopic and then clinical, eventually leading to a second intervention in 15 to 20% of cases. Certain risk factors for recurrence such as smoking, repeated and/or extensive resections, anoperineal involvement, myenteric plexitis, epithelioid granulomas, penetrating disease behaviour and lack of post-operative prophylactic treatment have been well established. Currently, measures to prevent post-operative recurrence are based mainly on smoking cessation in all patients and the prescription of anti-TNFα medications for patients with a high risk of recurrence (at least two risk factors for recurrence). However, new surgical techniques have recently been described which could modify post-operative prevention strategies. Kono's lateral anti-mesenteric anastomosis could significantly reduce clinical and endoscopic recurrence compared to conventional anastomosis techniques. Long latero-lateral isoperistaltic stricturoplasties have been shown to be feasible and are associated with a low rate of long-term symptomatic recurrence requiring surgery. In a preliminary series, intestinal resections with extensive mesenteric resection reduced the rate of recurrence in comparison with patients operated on conventionally (3% vs. 40% at five years). If the results of these new surgical techniques are confirmed, the indications for post-operative immunomodulatory treatments could be downgraded in patients currently considered to be at high risk of recurrence.

The RAGE signaling pathway is involved in intestinal inflammation and represents a promising therapeutic target for Inflammatory Bowel Diseases.

Inflammatory Bowel Diseases (IBD) are chronic inflammatory conditions of the intestinal tract. IBD are believed to result from an inappropriate immune response against the intestinal flora in genetically predisposed patients. The precise etiology of these diseases is not fully understood, therefore treatments rely on the dampening of symptoms, essentially inflammation, rather than on the cure of the disease. Despite the availability of biologics, such as anti-TNF antibodies, some patients remain in therapeutic failure and new treatments are thus needed. The multiligand receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor implicated in inflammatory reactions and immune system activation. Here, we investigated the role of RAGE in intestinal inflammation and its potential as a therapeutic target in IBD. We showed that RAGE was upregulated in inflamed tissues from IBD patients compared to controls. Rage-/- mice were less susceptible to intestinal and colonic inflammation development than WT mice. WT mice treated with the RAGE-specific inhibitor FPS-ZM1 experienced less severe enteritis and colitis. We demonstrated that RAGE could induce intestinal inflammation by promoting oxidative stress and endothelial activation which were diminished by FPS-ZM1 treatment. Our results revealed the RAGE signaling pathway as a promising therapeutic target for IBD patients.

Ileal or Anastomotic Location of Lesions Does Not Impact Rate of Postoperative Recurrence in Crohn's Disease Patients Classified i2 on the Rutgeerts Score.

BACKGROUND: The Rutgeerts score with 5 grades of severity (i0-i4) is a suitable endoscopic model to predict clinical recurrence following ileocolonic resection in Crohn's disease (CD). Definition of grade i2 includes lesions confined to the ileocolonic anastomosis (i2a) or moderate lesions on the neo-terminal ileum (i2b). The aim of the present study was to evaluate the probability of clinical recurrence in i2a and i2b patients. METHODS: This multicenter retrospective study included all CD patients classified i2 at the first postoperative ileocolonoscopy. The primary outcome was to evaluate the probability of clinical recurrence in patients classified i2a and i2b. The secondary outcome was to compare the rate of global recurrence of CD. RESULTS: Fifty patients were included: 23 were classified i2a and 27 were classified i2b. The median duration of follow-up was 40 (18.0-80.4) months in the i2a group and 53.5 (25.0-69.0) months in the i2b group (p = 0.9). The probability of clinical recurrence was not significantly different between patients classified i2a and i2b (p = 0.64). Median time to clinical recurrence after the first ileocolonoscopy and probability of global CD recurrence were not different between the two groups (p ≥ 0.19). CONCLUSIONS: The rate of clinical postoperative recurrence is not different in i2a and i2b patients. These results suggest that the same therapeutic strategy should be used in all patients classified i2 on the Rutgeerts score whatever the location of postoperative CD recurrence.

Gut: An underestimated target organ for Aluminum.

Since World War II, several factors such as an impressive industrial growth, an enhanced environmental bioavailability and intensified food consumption have contributed to a significant amplification of human exposure to aluminum. Aluminum is particularly present in food, beverages, some drugs and airbone dust. In our food, aluminum is superimposed via additives and cooking utensils. Therefore, the tolerable intake of aluminum is exceeded for a significant part of the world population, especially in children who are more vulnerable to toxic effects of pollutants than adults. Faced with this oral aluminum influx, intestinal tract is an essential barrier, especially as 38% of ingested aluminum accumulates at the intestinal mucosa. Although still poorly documented to date, the impact of oral exposure to aluminum in conditions relevant to real human exposure appears to be deleterious for gut homeostasis. Aluminum ingestion affects the regulation of the permeability, the microflora and the immune function of intestine. Nowadays, several arguments are consistent with an involvement of aluminum as an environmental risk factor for inflammatory bowel diseases.

Toxicological consequences of experimental exposure to aluminum in human intestinal epithelial cells.

Aluminum (Al), a non-essential element, is ubiquitous in industrialized societies. Whereas adult intake is estimated between 3 and 12 mg/day according to dietary aluminum studies conducted in many countries, it is not known if aluminum may have a toxic effect on intestinal epithelium. The aim of this work was to evaluate the cytotoxicity and RNA expression patterns induced in HT-29 cells by aluminum. Both classical toxicological methods and a global transcriptomic approach were used. Cytotoxicity determined by MTT assay showed a time and dose dependent decrease of cell viability in aluminum treated cells compared to control cells. Cell cycle analysis by flow cytometry revealed that aluminum induced accumulation of cells in phase G0/G1, associated with a decrease in the proportion of cells in S and G2/M phases. Aluminum led to apoptosis as evidenced by nuclear morphology changes and mitochondrial membrane perturbations, and induced reactive oxygen species generation. Transcriptomic pattern argued in favor of pro-tumorigenic and pro-inflammatory effects of aluminum in intestinal epithelial cells. These results highlight several pathways by which aluminum has a disturbing impact on intestinal epithelial cells, supporting that the effects of aluminum on intestine warrants further investigation.

The schistosome glutathione S-transferase P28GST, a unique helminth protein, prevents intestinal inflammation in experimental colitis through a Th2-type response with mucosal eosinophils.

Intestinal helminth parasites are potent inducers of T helper type 2 (Th2) response and have a regulatory role, notably on intestinal inflammation. As infection with schistosomes is unlikely to provide a reliable treatment of inflammatory bowel diseases, we have investigated the beneficial effect of a schistosome enzymatic protein, the 28-kDa glutathione S-transferase (P28GST), on the modulation of disease activity and immune responses in experimental colitis. Our results showed that immunization with recombinant P28GST is at least as efficient as established schistosome infection to reduce colitis lesions and expression of pro-inflammatory cytokines. Considering underlying mechanisms, the decrease of inflammatory parameters was associated with the polarization of the immune system toward a Th2 profile, with local and systemic increases of interleukin (IL)-13 and IL-5. Dense eosinophil infiltration was observed in the colons of P28GST-immunized rats and mice. Depletion of eosinophils by treatment with an anti-Siglec-F monoclonal antibody and use of IL-5-deficient mice led to the loss of therapeutic effect, suggesting the crucial role for eosinophils in colitis prevention by P28GST. These findings reveal that immunization with P28GST, a unique recombinant schistosome enzyme, ameliorates intestinal inflammation through eosinophil-dependent modulation of harmful type 1 responses, representing a new immuno-regulatory strategy against inflammatory bowel diseases.

In vivo efficacy of microbiota-sensitive coatings for colon targeting: a promising tool for IBD therapy.

The first proof of concept in vivo for a new type of microbiota-sensitive film coatings allowing for colon targeting is presented. The efficacy of these polysaccharide barriers to optimize drug release for the treatment of inflammation is demonstrated in an experimental colitis model with Wister rats. 5-Aminosalicylic acid (5-ASA) pellets were prepared by extrusion-spheronization and coated with Nutriose:ethylcellulose (EC) 1:4 or peas starch:ethylcellulose 1:2 blends. The pellets were mixed with standard chow, and the daily drug dose was 150mg/kg. For reasons of comparison, also commercially available Pentasa pellets and placebo pellets were studied. At day 3 after the beginning of the treatment, colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS). Animals were sacrificed on day 6. Macroscopic and histological evaluations of colitis were performed blindly. In addition, inflammatory markers were evaluated using ELISA and real-time PCR. Rats receiving TNBS and placebo pellets developed a severe colitis in the distal half of the colon. 5-ASA administered in the form of Pentasa pellets reduced macroscopic inflammation by only 5%. In contrast, the colon lesions were much less severe upon treatment with Nutriose:EC- and peas starch:EC-coated pellets: The macroscopic score was reduced by 25 and 24%, respectively. Decreases of 37 and 38% of the histological lesions confirmed the efficacy of these new colon targeting systems. Also, inflammatory markers (MPO, IL-1ß mRNA, TNF mRNA) were significantly decreased in rats receiving Nutriose:EC- and peas starch:EC-coated pellets compared to Pentasa pellets. Furthermore, real-time PCR analysis indicated increased activation of the target receptor PPAR-γ and the HMGCS2 gene in rats upon administration of 5-ASA loaded Nutriose:EC- and peas starch:EC pellets compared to the commercial product. Also, HPLC-MS/MS analysis of plasma samples demonstrated that the level of the main metabolite of the drug (N-acetyl-5-ASA) was much lower upon administration of Nutriose:EC or peas starch:EC coated pellets compared to Pentasa pellets, indicating that undesired premature drug release in the upper gastrointestinal tract was more effectively hindered. In addition to the rat study, in vivo imaging of transgenic mice expressing the luciferase gene evidenced much more pronounced PPAR-γ activation upon 5-ASA administration in the form of Nutriose:EC-coated pellets versus Pentasa pellets. All these results clearly demonstrate the superiority of these microbiota-sensitive polysaccharide-based film coatings for colon targeting in vivo.

[Autologous stem cell transplantation for autoimmune diseases: recommendations from the SFGM-TC]. / Autogreffe des cellules souches hématopoïétiques dans les maladies auto-immunes : recommandations de la SFGM-TC.

Autologous hematopoietic stem cell transplantation is a valid alternative to immunosuppressive treatment in patients with auto-immune disease; however, the role of this approach remains subject to debate. In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from all of its member centers. These workshops took place in September 2013 in Lille. In this article we give an overview regarding the indications of autologous stem cell transplantation in auto-immune diseases as well as recommendations regarding post-transplant follow-up of patients.

Aluminum enhances inflammation and decreases mucosal healing in experimental colitis in mice.

The increasing incidence of inflammatory bowel diseases (IBDs) in developing countries has highlighted the critical role of environmental pollutants as causative factors in their pathophysiology. Despite its ubiquity and immune toxicity, the impact of aluminum in the gut is not known. This study aimed to evaluate the effects of environmentally relevant intoxication with aluminum in murine models of colitis and to explore the underlying mechanisms. Oral administration of aluminum worsened intestinal inflammation in mice with 2,4,6-trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis and chronic colitis in interleukin 10-negative (IL10(-/-)) mice. Aluminum increased the intensity and duration of macroscopic and histologic inflammation, colonic myeloperoxidase activity, inflammatory cytokines expression, and decreased the epithelial cell renewal compared with control animals. Under basal conditions, aluminum impaired intestinal barrier function. In vitro, aluminum induced granuloma formation and synergized with lipopolysaccharide to stimulate inflammatory cytokines expression by epithelial cells. Deleterious effects of aluminum on intestinal inflammation and mucosal repair strongly suggest that aluminum might be an environmental IBD risk factor.

Recent advances in the development of selective CB(2) agonists as promising anti-inflammatory agents.

The high distribution of CB(2) receptors in immune cells suggests their important role in the control of inflammation. Growing evidence offers this receptor as an attractive therapeutic target: CB(2) selective agonists are able to modulate inflammation without triggering psychotropic effects. This review will summarize the literature on the implication of CB(2) in inflammation and CB(2) selective agonists with anti-inflammatory activity.

Increased lymphatic vessel density and lymphangiogenesis in inflammatory bowel disease.

BACKGROUND: Involvement of the lymphatic system in inflammatory bowel disease (IBD) has been suggested. AIMS: To examine the density and distribution of lymphatic vessels (LV) within inflamed and non-inflamed wall sections of IBD patients compared with controls, and to evaluate expression of major lymphangiogenic factors. METHODS: Ileal and colon specimens of 22 patients with Crohn's disease (CD), 16 patients with ulcerative colitis (UC) and 11 controls were studied. Quantification of LV was performed using immunohistochemistry with podoplanin and D2-40 antibodies on seven randomly selected fields. Mucosal expression of podoplanin and lymphangiogenic factor mRNA was measured using PCR. RESULTS: In CD patients, lymphatic density was significantly increased in non-inflamed and inflamed ileal (P < 0.01 and P < 0.001) and colonic (P < 0.01 and P < 0.001) mucosa compared to controls. Podoplanin mRNA levels were similar in non-inflamed mucosal areas and controls, whereas a four- and sixfold increase was seen in inflamed ileal and colonic areas (P < 0.05). In UC, lymphatic density increased fourfold in non-inflamed (P < 0.001) and fivefold in inflamed colonic mucosa (P < 0.001) compared with controls. An increase in podoplanin mRNA levels was seen in both non-inflamed and inflamed areas (P < 0.01) compared with controls. In CD and UC, lymphatics were found throughout the inflamed mucosa, including the upper half of the lamina propria. Expression of lymphangiogenic factors was similar in patients and controls. CONCLUSIONS: Increased density of lymphatic vessels is a constant feature of IBD and is present in non-inflamed areas. It is transmural in CD and confined to the mucosa in UC. Its origin remains unclear.

[Nuclear receptor PPAR and hepatology: pathophysiological and therapeutical aspects]. / Récepteurs nucléaires PPAR et hépatologie: implications physiopathologiques et thérapeutiques.

In last few years, the topic of nuclear receptor has been developed in the field of hepatology allowing envisaging therapeutic strategies for the most frequent chronic liver diseases. Peroxysome proliferator-activated receptors (PPAR) contribute to wide physiological processes within the liver such as lipid/glucid metabolisms, inflammatory response, cell differenciation and cell cycle. In vitro experiments and animal studies showed that PPARalpha discloses anti-inflammatory property and PPARgamma discloses anti-inflammatory, antifibrogenic and antiproliferative properties in the liver. Main available agonists are fibrates (PPARalpha) used for 20 years in cases of lipid metabolism abnormalities and glitazones (PPARgamma) used since 2000 for type 2 diabetes. In terms of therapy, animal studies and human trials have been conducted in steatopathies. However, clinicians have to be aware of potential specific side effects related to glitazones especially on cardiovascular system.

Successful induction of tolerance to infliximab in patients with Crohn's disease and prior severe infusion reactions.

AIM: To appraise the tolerance and efficacy of an induction of tolerance protocol to infliximab permitting the re-administration of the drug to patients with Crohn's disease having had infusion reactions requiring suspension of treatment. METHODS: Fourteen patients were included in the induction of tolerance protocol. Each infusion of infliximab (5 mg/kg) was divided into 11 escalating 15 min increments over a 3-h time period. The induction of tolerance procedure was repeated for subsequent infusions. RESULTS: Ten patients (71.4%) received all the three infusions for the induction treatment. Nine (64.3%) had a significant response and six (48.8%) still benefited from infliximab infusions. Seven patients (50%) achieved a complete remission, after a mean of 2.5 (two to three) infusions. Four patients (28.6%) had no response and the protocol was stopped. Three patients (21.4%) experienced mild immediate hypersensitivity reactions, which were controlled, two patients (14.2%) experienced severe immediate hypersensitivity reactions, leading to interruption of the treatment and one patient developed a delayed hypersensitivity reaction. CONCLUSION: Our induction of tolerance protocol allows some patients who have experienced severe or repetitive infusion reactions to infliximab to be safely retreated with the drug in a hospitalized setting, with a clinical response achieved in a majority of these patients.

PPARgamma as a new therapeutic target in inflammatory bowel diseases.

The peroxisome proliferator activated receptor gamma(PPARgamma) is a nuclear receptor highly expressed in the colon and playing a key role in bacterial induced inflammation. Regulation of colon inflammation by this receptor has been well demonstrated in many experimental models of colitis but also in patients with ulcerative colitis, characterised by impaired expression of PPARgamma confined to their colon epithelial cells. Recent data showing that PPARgamma was the major functional receptor mediating the common aminosalicylate activities in inflammatory bowel diseases (IBD) have also reinforced the roles of this receptor in the control of intestinal inflammation. The aims of this review are to discuss the potential roles of PPARgamma in the physiopathology of IBD, as well as the emerging therapeutic strategies targeting this receptor.

Review article: mode of action and delivery of 5-aminosalicylic acid - new evidence.

The effectiveness of sulfasalazine depends on the splitting of the diazo bond in the molecule by the action of bacteria in the large bowel, releasing the pharmacologically active moiety, 5-aminosalicylic acid. The development of pH-dependent, delayed-release formulations of 5-aminosalicylic acid abolished the toxicity associated with the sulfapyridine part of sulfasalazine. 5-aminosalicylic acid is now believed to act by activating a class of nuclear receptors involved in the control of inflammation, cell proliferation, apoptosis and metabolic function, the gamma form of peroxisome proliferator-activated receptors. These receptors are expressed at particularly high levels in colon epithelial cells, where their expression appears to be at least in part stimulated by gut bacteria. Other drugs known to act via peroxisome proliferator-activated receptor-gamma, such as rosiglitazone and the selective peroxisome proliferator-activated receptor-gamma ligand GW1929, can be displaced from their binding sites on the peroxisome proliferator-activated receptor-gamma molecule by 5-aminosalicylic acid at concentrations of 5-aminosalicylic acid that correspond with the concentrations found in the lumen of ulcerative colitis patients taking oral mesalazine. Genetically engineered heterozygous knockout mice (peroxisome proliferator-activated receptor-gamma+/-) are particularly susceptible to colonic inflammation, and inflammation is more severe in these mice, in response to chemicals that induce experimental colonic ulcers. In these experimental models, 5-aminosalicylic acid is ineffective in peroxisome proliferator-activated receptor-gamma+/- mice. This new insight provides a mechanistic foundation for the possibility that long-term treatment with 5-aminosalicylic acid can reduce the risk of colorectal cancer in patients with ulcerative colitis.

[Fatal fulminant Epstein-Barr virus hepatitis]. / Hépatite fulminante fatale à Epstein-Barr virus.

Infectious mononucleosis is a common and benign disease. Although hepatic cytolysis is common during infectious mononucleosis, fulminant hepatitis is rare. We report an observation of a fatal fulminant hepatitis complicating a primary EBV infection in a 15 year-old male.

Mu opioid receptor expression is increased in inflammatory bowel diseases: implications for homeostatic intestinal inflammation.

BACKGROUND AND AIMS: Recent studies with mu opioid receptor (MOR) deficient mice support a physiological anti-inflammatory effect of MOR at the colon interface. To better understand the potential pharmacological effect of certain opiates in inflammatory bowel diseases (IBD), we (1) evaluated the regulation in vivo and in vitro of human MOR expression by inflammation; and (2) tested the potential anti-inflammatory function of a specific opiate (DALDA) in inflamed and resting human mucosa. PATIENTS AND METHODS: Expression of MOR mRNA and protein was evaluated in healthy and inflamed small bowel and colonic tissues, isolated peripheral blood mononuclear cells and purified monocytes, and CD4+ and CD8+ T cells from healthy donors and IBD patients. The effect of cytokines and nuclear factor kappaB (NFkappaB) activation on MOR expression in lymphocyte T and monocytic human cell lines was assessed. Finally, DALDA induced anti-inflammatory effect was investigated in mucosal explants from controls and IBD patients. RESULTS: MOR was expressed in ileal and colonic enteric neurones as well as in immunocytes such as myeloid cells and CD4+ and CD8+ T cells. Overexpressed in active IBD mucosa, MOR was significantly enhanced by cytokines and repressed by NFkappaB inhibitor in myeloid and lymphocytic cell lines. Furthermore, ex vivo DALDA treatment dampened tumour necrosis factor alpha mRNA expression in the colon of active IBD patients. CONCLUSIONS: Given the increased expression of MOR and the ex vivo beneficial effect of DALDA in active IBD, natural and/or synthetic opioid agonists could help to prevent overt pathological intestinal inflammation.

[Desensitisation to infliximab in patients with Crohn's disease]. / Accoutumance médicamenteuse a l'infliximab dans la maladie de Crohn.

BACKGROUND: Infliximab is a chimeric monoclonal antibody directed against tumour necrosis factor-alpha that has been shown to improve chronic refractory and fistulating Crohn's disease. Infliximab infusions have been associated both with immediate and delayed reactions. MATERIAL AND METHODS: Desensitisation was performed in four patients who had experienced immediate reactions to infliximab infusions and in one who had developed a delayed reaction. No therapeutic alternatives were available for these patients. Before desensitisation, skin tests were performed. RESULTS: Skin-tests were negative for all patients. Desensitisation was performed with serial dilutions of infliximab with monitoring of vital signs before each increment. After parenteral desensitisation, all five patients were able to tolerate infliximab infusion without complications or any requirement for antihistamines or steroids. However, two patients who had initially presented with an immediate reaction to infliximab experienced arthralgia and myalgia similar to a "serum sickness-type" of reaction 6 to 10 days after desensitisation. CONCLUSION: Even if there is no evidence of an allergic mechanism in infusion reactions to infliximab, successful desensitization can be achieved for patients experiencing acute reactions. The mechanism of desensitisation remains presently unknown. It is not yet possible to say if desensitization will be effective in preventing delayed reactions.