MicroRNAs in inflammatory bowel disease: What do we know and what can we expect?

MicroRNAs (miRNAs), small non-coding RNAs composed of 18–24 nucleotides, are potent regulators of gene expression, contributing to the regulation of more than 30% of protein-coding genes. Considering that miRNAs are regulators of inflammatory pathways and the differentiation of intestinal epithelial cells, there is an interest in exploring their importance in inflammatory bowel disease (IBD). IBD is a chronic and multifactorial disease of the gastrointestinal tract; the main forms are Crohn's disease and ulcerative colitis. Several studies have investigated the dysregulated expression of miRNAs in IBD, demonstrating their important roles as regulators and potential biomarkers of this disease. This editorial presents what is known and what is expected regarding miRNAs in IBD. Although the important regulatory roles of miRNAs in IBD are clearly established, biomarkers for IBD that can be applied in clinical practice are lacking, emphasizing the importance of further studies. Discoveries regarding the influence of miRNAs on the inflammatory process and the exploration of their role in gene regulation are expected to provide a basis for the use of miRNAs not only as potent biomarkers in IBD but also as therapeutic targets for the control of inflammatory processes in personalized medicine.

Evaluation of a Standardized Extract Obtained from Cashew Apple (Anacardium occidentale L.) Bagasse in DSS-Induced Mouse Colitis

Inflammatory bowel diseases (IBD) include Crohn's disease and ulcerative colitis. Several studies relate eating habits to different aspects of IBD, such as progression and worsening of the clinical condition. Therefore, many natural products (NPs) such as polyphenols and carotenoids have been identified as promising agents in supporting IBD. An interesting source for obtaining bioactive NPs is the by-products of the food industry. The present study evaluated the potential beneficial effect of a standardized extract (CAE) obtained from cashew apple bagasse in the dextran sulfate sodium (DSS)-induced ulcerative colitis model in mice. This was the first time that CAE had been evaluated in this experimental model. Chemical evaluation of CAE identified carotenoids (96.28 ± 0.15 mg/100 g), phenolic compounds (37.49 ± 0.64 mg/100 g), and a mixture of anacardic acids (C15:3 = 94.2 ± 0.6 mg/100 g; C15:2 = 108.4 ± 0.1 mg/100 g; C15:1 = 214.8 ± 0.2 mg/100 g). Administration of CAE (500 mg/kg, 4 days, p.o.) after DSS challenge was more effective in delaying disease progression compared with prior treatment (500 mg/kg, 30 days, p.o.), according to the disease activity index. However, no treatment strategy with CAE was able to prevent or inhibit disease progression, since all parameters evaluated (macroscopic, biochemical, and histopathological) in CAE-treated animals were similar to those observed in DSS-challenged animals. Despite the high dose (500 mg/kg), the standardized extract (CAE) did not result in an effective concentration of carotenoids. Furthermore, as some anacardic acids have been reported as histone acetyltransferases inhibitors, there could be a possible antagonistic relationship between carotenoids and anacardic acids. Complementary research will be necessary to test the hypothesis of antagonism. Thus, an optimized extract, with an even higher concentration of carotenoids, obtained from cashew apple bagasse, can be developed as a possible adjuvant food supplement for inflammatory bowel diseases.

Intestinal Microbiota and miRNA in IBD: A Narrative Review about Discoveries and Perspectives for the Future

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC) and comprises a chronic gastrointestinal tract disorder characterized by hyperactive and dysregulated immune responses to environmental factors, including gut microbiota and dietary components. An imbalance of the intestinal microbiota may contribute to the development and/or worsening of the inflammatory process. MicroRNAs (miRNAs) have been associated with various physiological processes, such as cell development and proliferation, apoptosis, and cancer. In addition, they play an important role in inflammatory processes, acting in the regulation of pro- and anti-inflammatory pathways. Differences in the profiles of miRNAs may represent a useful tool in the diagnosis of UC and CD and as a prognostic marker in both diseases. The relationship between miRNAs and the intestinal microbiota is not completely elucidated, but recently this topic has gained prominence and has become the target of several studies that demonstrate the role of miRNAs in the modulation of the intestinal microbiota and induction of dysbiosis; the microbiota, in turn, can regulate the expression of miRNAs and, consequently, alter the intestinal homeostasis. Therefore, this review aims to describe the interaction between the intestinal microbiota and miRNAs in IBD, recent discoveries, and perspectives for the future.

Dietary intervention with avocado (Persea americana Mill.) ameliorates intestinal inflammation induced by TNBS in rats

Nutritional interventions have been shown to be an interesting approach for the treatment of chronic diseases, including inflammatory bowel disease (IBD). Persea americana Mill. (avocado), is a potential food to be used for the prevention or treatment of intestinal inflammation, due to its nutritional value and pharmacological effects. In this study we evaluated if the dietary intervention with avocado fruit pulp could as an intestinal anti-inflammatory diet using a trinitrobenzenesulfonic acid (TNBS) model of intestinal inflammation in rats. For this purpose, 5, 10 or 20% of avocado fruit pulp was incorporated in the diet of rats, for 21 days before and 7 days after TNBS-induced intestinal inflammation. Dietary intervention with avocado fruit pulp (20%) decreased the extension of colonic lesions (1.38 ± 0.99 vs. 2.67 ± 0.76 cm), weight/length colon ratio (151.03 ± 31.45 vs. 197.39 ± 49.48 cm), inhibited myeloperoxidase activity (891.2 ± 243.2 vs 1603 ± 158.2 U/g), reduced tumor necrosis factor-α (53.94 ± 6.45 vs. 114.9 ± 6.21 pg/mg), interleukin-1β (583.6 ± 106.2 vs. 1259 ± 81.68 pg/mg) and interferon gamma (27.95 ± 2.97 vs. 47.79 ± 3.51 pg/mg) levels and prevented colonic glutathione depletion (2585 ± 77.2 vs 1778 ± 167.2 nmol/g). The consumption of enriched diet with 20% avocado pulp by 28 days did not promote any alterations in the biochemical or behavioral parameters evaluated. Avocado showed intestinal anti-inflammatory activity, modulating immune response, and acting as antioxidant. The dietary intervention with avocado was safe, suggesting its potential as a complementary treatment in intestinal inflammation.

Cashew apple byproduct: Gastroprotective effects of standardized extract

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of gastric mucosa lesions in the adult population has increased mainly due to the continued use of nonsteroidal anti-inflammatory drugs (NSAIDs). The cashew (Anacardium occidentale L.) is a tropical tree, cultivated in several countries, whose barks, leaves and pseudofruit (cashew apple) are popularly used in traditional medicine for the treatment of many diseases, including gastric ulcer.

AIM

Our study evaluated the potential gastroprotective effect of the carotenoid and anacardic acids-enriched aqueous extract (CAE), prepared from cashew apple pomace, in the dose-repeated acetylsalicylic acid (ASA)-induced gastric lesions model in rats.

MATERIAL AND METHODS

After randomly distribution into five group (G1 - G5, n = 8 animals/group), male Wistar rats were daily treated with ASA solution (200 mg/kg, 5 ml/kg, G2 - G5) or potable water (Satellite group, G1) during 14 days. From 8th to 14th experimental day, rats in G3 - G5 groups were orally treated with CAE (50, 100 and 500 mg/kg, 5 ml/kg, respectively). Body weight was measured on 0, 7th and 14th day. On the 14th experimental day, all surviving animals were euthanized for macroscopic evaluation of the inner organs and stomach removal. After weighting, each stomach was properly prepared for biochemical analysis [myeloperoxidase activity (MPO), reduced glutathione analysis (GSH), IL-1β, CXCL2/MIP-2, TNF-α and IL-10 levels].

RESULTS

At the most efficient dose (100 mg/kg, p.o.), CAE-treated animals showed a slight improvement in the macroscopic aspect of gastric mucosa associated with significant (p < 0.05) reduced levels of IL-1β, CXCL2/MIP-2, and MPO activity besides increased levels of GSH (partially), and IL-10 in stomach tissues.

CONCLUSIONS

The present study demonstrated that the carotenoid and anacardic acids-enriched extract obtained from cashew apple pomace is a promising raw material for the development of herbal medicine and/or functional food supplements for the adjuvant treatment of NSAIDs-induced gastric ulcers.

Spilanthol, the Principal Alkylamide from Acmella oleracea, Attenuates 5-Fluorouracil-Induced Intestinal Mucositis in Mice

Mucositis is one of the commonest side effects in cancer patients undergoing treatment with radiotherapy and/or chemotherapy, and it currently lacks appropriate and effective treatment. Acmella oleracea, a species of flowering herb from South America, contains spilanthol, an alkylamide that has several pharmacological properties, including anesthetic, analgesic, and anti-inflammatory activities. Therefore, the purpose of this work was to evaluate the effect of spilanthol in intestinal mucositis in Swiss mice induced by 5-fluorouracil (5-FU), an antineoplastic agent administered systemically for the treatment of many different cancers. The repeated administration of 5-FU resulted in intestinal mucositis and consequent decreased food intake, together with weight loss, in all the animals. Daily administration of spilanthol significantly lowered the severity of intestinal mucositis, reducing histopathological changes and increasing the villus height in the animals treated with spilanthol at a dosage of 30 mg/kg (p < 0.0044) compared to a group exposed only to 5-FU. A decrease of myeloperoxidase activity was also observed in the animals treated with 30 mg/kg of spilanthol (p < 0.05), although several pro-inflammatory cytokines were not quantifiable in any group. In conclusion, the data demonstrated that spilanthol effectively reduced inflammation in a mouse model of intestinal mucositis induced by 5-FU, and that the compound might be a promising therapeutic candidate for the prevention and treatment of this condition.