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.

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.

Controlled delivery of a new broad spectrum antibacterial agent against colitis: In vitro and in vivo performance.

Coated pellets and mini-tablets were prepared containing a new broad spectrum antibacterial agent: CIN-102, a well-defined, synergistic blend of trans-cinnamaldehyde, trans-2-methoxycinnamaldehyde, cinnamyl acetate, linalool, ß-caryophyllene, cineol and benzyl benzoate. The aim was to provide a new treatment method for colitis, especially for Inflammatory Bowel Disease (IBD) patients. Since the simple oral gavage of CIN-102 was not able to reduce the pathogenic bacteria involved in colitis (rat model), the drug was incorporated into multiparticulates. The idea was to minimize undesired drug release in the upper gastrointestinal tract and to control CIN-102 release in the colon, in order to optimize the resulting antibiotic concentration at the site of action. A particular challenge was the fact that CIN-102 is a volatile hydrophobic liquid. Pellet cores were prepared by extrusion-spheronization and coated with polymer blends, which are sensitive to colonic bacterial enzymes. Mini-tablets were prepared by direct compression. The release of the main compound of CIN-102 (cinnamaldehyde, 86.7% w/w) was monitored in vitro. Optimized coated pellets and mini-tablets were also tested in vivo: in seven-week-old, male mice suffering from dextran sodium sulfate induced colitis. Importantly, both types of multiparticulates were able: (i) to significantly reduce the number of luminal and mucosal enterobacteria in the mice (the levels of which are increased in the disease state), and (ii) to improve the clinical course of the intestinal inflammation (decrease in the percentages of mice with bloody stools and diarrhea). Thus, the proposed coated pellets and matrix mini-tablets allowing for controlled CIN-102 release show a promising potential for new treatment methods of colitis.

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.