Crohn's disease (CD) is an inflammatory bowel disease (IBD), whose pathogenesis and aetiology remains unclear. Trinitrobenzenesulfonic acid (TNBS)-induced colitis is a commonly utilised animal model because it shares features of human CD. Polyphenols have been studied widely by their anti-inflammatory, antioxidant and immunomodulatory properties. Chilean berry Aristotelia chilensis (ACh) belongs to the ‘super fruit’ family due to its high content of phenolic antioxidants. Our objective was to investigate the clinical and histopathological impact of ACh extract on TNBS-induced colitis. Male Balb/c mice of 8 months old were used for CD induction, administrating via intracolonic 125 mg/kg of TNBS with 50% ethanol (EtOH). Control group received only 50% ethanol. Ach extract was administered by orogastric tube (500 mg/kg/day) for 1 week prior to the induction of disease (Preventive group) and 4 days after TNBS administration (Treatment group). TNBS treated mice exhibited significantly body weight loss compared with the Control group (EtOH). The administration of ACh extract significantly improved the body weight in Preventive and Treatment groups (Figure 1). For the histopathological analysis, we used the whole colon in the same slide (Figure 2). Colonic tissue of the different groups showed colon shortening as a marker of tissue inflammation (Figure 3). Microscopically, we observed transmural inflammation with cell infiltration, ulcerations and loss of goblet cells in the TNBS group. ACh extract largely restored the normal histological structure of the colonic mucosa and submucosa (Figure 4). Figure 1. Effect of ACh extract on body weight. Figure 2. Rolled colon for the microscopic evaluation of the whole organ. H&E, 4×. Figure 3. Ach extract prevents shortening of large intestine. Figure 4. Microscopic evaluation of colonic tissue. This animal model shows the progress of a transmural inflammation with tissue damage that resembles the development of human CD. The administration of polyphenolic ACh extract may exert protective effects and therapeutic against TNBS-induced colitis.

BACKGROUND:Colorectal cancer (CRC) is the most severe complication in inflammatory bowel disease (IBD). In the present study we investigated different mechanistic links between chronic colonic inflammation and its progression to adenocarcinoma. Along these lines, given that adrenomedullin (AM) has been implicated in carcinogenesis, we also analyzed changes in its colonic expression. METHODS:Mice were exposed to 5, 10, and 15 cycles of dextran sulfate sodium (DSS); each cycle consisted of 0.7% DSS for 1 week followed by distilled water for 10 days. After each period, macroscopic and histological studies, as well as characterization of inflammatory and tumor biomarkers, were carried out. RESULTS:The disease activity index (DAI) showed that the disease was present from the third cycle and it gradually increased during the course of DSS treatment. Macroscopic tumors were only seen after 15 cycles, and microscopic study showed that inflammation, dysplasia, and adenocarcinomas correlated with DSS cycles. β-Catenin and proliferating cell nuclear antigen expressions progressively increased in animals treated with the different cycles of DSS. TNF-α and IFN-γ showed the highest production at the tenth cycle. COX-2, mPGES-1, and iNOS levels were also appreciably higher at the fifth and tenth cycles. Moreover, we observed a progressive enhancement in AM expression and changes in its intracellular location during the progression of the disease. CONCLUSIONS:Our results show an early induction of proinflammatory factors, which may contribute to the development of colon cancer, as well as demonstrate, for the first time, the expression of AM in IBD-derived CRC.

Adrenomedullin (AM) is a 52 amino acid peptide and member of the calcitonin gene-related peptide (CGRP) super family. Given that AM has emerged as a potential immuno-regulatory and anti-inflammatory agent in various experimental models, this study has deepened into its possible therapeutic effect in intestinal inflammation analyzing the responses in both acute and chronic (14 and 21 days) phases of TNBS-induced colitis in rats. In the acute model, AM treatment reduced the incidence of diarrhea and the severity of colonic damage, and improved the survival rate at the three doses assayed (50, 100, and 200 ng/kg animal). AM administration was able to reduce the early production of TNF-α and collaborated to maintaining basal levels of IFN-γ and IL-10. In the chronic studies the peptide attenuated the extent of the damage with lesser incidence of weight loss and diarrhea (50 and 100 ng/kg animal). Cellular neutrophil infiltration, with the subsequent increase in myeloperoxidase (MPO) levels caused by TNBS, was reduced after chronic AM administration. The peptide played a role in the evolution of Th1/Th2 cytokines balance and chronic disease recuperation: levels of proinflammatory TNF-α and IFN-γ decreased and anti-inflammatory IL-10 increased significantly. Cyclooxygenase-2 (COX-2) and nitric oxide synthase (iNOS) protein expression were not modified by AM administration, although a reduction of nitric oxide (NO) production could be detected in the chronic model. These results support a role of AM as an anti-inflammatory factor with beneficial effects in intestinal inflammatory colitis.

The objective of the present study has been to advance knowledge of the gastric role played by the amino acid L-Arginine (L-Arg) in the evolution of a chronic gastric ulcer. In order to clarify it, L-Arg alone or together with Ibuprofen have been administrated in an experimental acetic acid chronic ulcer, analysing characteristic parameters of an active curative process, such as PGE2 production, COX expression, and also angiogenesis, proliferation/apoptosis and growth factors expression. Our results reveal that L-Arg is favourable in the healing process improving the curative course. Ibuprofen caused a delay in ulcer healing, more evident 14 days after ulcer induction; COX-2 expression was increased at the 7th day although no signal of protein could be detected after 14 days; PGE2 production was inhibited in intact and ulcerated areas at both times assayed. In contrast, treatment with L-Arg reduced the delay of the lesion, the increment in COX-2 expression induced by Ibuprofen, and was able to maintain PGE2 levels similar to the control group after 14 days. Additionally, the histological study showed that the healing effects of L-Arg might be associated with an increased angiogenesis and FGF-2 expression. These actions could be considered key factors in the healing response associated with L-Arg administration. However, the proliferation study assayed with the PCNA-immunostaining method did not reveal significant differences, as the same as the apoptosis analysis. In conclusion, the coupling of L-Arg to Ibuprofen is an attractive alternative to Ibuprofen administration alone because it not only attenuates but also improves the evolution of chronic lesions through mechanisms that implicate endogenous PG and FGF-2-associated pathways, which allow an increase of angiogenesis process.