Intestinal anti-inflammatory effect of the probiotic Saccharomyces boulardii in DSS-induced colitis in mice: Impact on microRNAs expression and gut microbiota composition.

The beneficial effects exerted by probiotics in inflammatory bowel disease (IBD) are well known, although their exact mechanisms have not been fully elucidated, and only few studies have focused on their impact on selected miRNAs and the gut microbiota composition. Therefore, our aim was to correlate the intestinal anti-inflammatory activity of the probiotic Saccharomyces boulardii in the dextran sodium sulphate (DSS) model of mouse colitis and the changes induced in miRNA expression and gut microbiota populations. Probiotic was given orally (5×109 CFU) to C57BL/6 mice for 26 days. After 2 weeks, the colitis was induced adding DSS to the drinking water. Mice were scored daily using a Disease Activity Index (DAI). After sacrifice, the colonic specimens were evaluated by determining the expression of inflammatory markers and micro-RNAs by qRT-PCR. Moreover, changes in microbiota populations were evaluated by pyrosequencing. Probiotic ameliorated the colonic damage induced by DSS, as evidenced by lower DAI values and colonic weight/length compared with untreated mice. The treatment modified the colonic expression of different inflammatory markers and the epithelial integrity proteins, and induced changes in micro-RNAs expression. Moreover, microbiota characterization showed that probiotic treatment increased bacterial diversity, thus ameliorating the dysbiosis produced by DSS-colitis. Saccharomyces boulardii exerted intestinal anti-inflammatory effects in DSS-mouse colitis, through the modulation in the immune response, involving modification of altered miRNA expression, being associated to the improvement of the inflammation-associated dysbiosis in the intestinal lumen, which could be of great interest to control the complex pathogenesis of IBD.

Differential intestinal anti-inflammatory effects of Lactobacillus fermentum and Lactobacillus salivarius in DSS mouse colitis: impact on microRNAs expression and microbiota composition.

SCOPE: To compare the intestinal anti-inflammatory effects of two probiotics Lactobacillus fermentum and Lactobacillus salivarius in mouse colitis, focusing on their impact on selected miRNAs and microbiota composition. METHODS AND RESULTS: Male C57BL/6J mice were randomly assigned to four groups (n = 10): non-colitic, DSS colitic and two colitic groups treated with probiotics (5 × 108 CFU/mouse/day). Both probiotics ameliorated macroscopic colonic damage. They improved the colonic expression of markers involved in the immune response, and the expression of miR-155 and miR-223. L. fermentum also restored miR-150 and miR-143 expression, also linked to the preservation of the intestinal barrier function. Besides, these beneficial effects were associated with the amelioration of the microbiota dysbiosis and a recovery of the SCFAs- and lactic acid-producing bacterial populations, although only L. fermentum improved Chao richness, Pielou evenness and Shannon diversity. Moreover, L. fermentum also restored the Treg cell population in MLNs and the Th1/Th2 cytokine balance. CONCLUSION: Both probiotics exerted intestinal anti-inflammatory effects in DSS-mouse colitis, maybe due to their ability to restore the intestinal microbiota homeostasis and modulate the immune response. L. fermentum showed a greater beneficial effect compared to L. salivarius, which makes it more interesting for future studies.

Immunomodulatory properties of Olea europaea leaf extract in intestinal inflammation.

SCOPE: Extracts from olive (Olea europaea) leaves are used in Mediterranean traditional medicine as anti-inflammatory agents. They contain antioxidant phenolic compounds, such as oleuropeoside, which could be interesting for the treatment of inflammatory conditions associated with oxidative stress in humans, including inflammatory bowel disease. METHODS AND RESULTS: The anti-inflammatory effects of olive leaf extract (0.5-25 mg/kg) were studied in two mice models of colitis (DSS and DNBS). Olive leaf extract (0.1-100 µg/mL) immunomodulatory effects were also investigated in different cell types and in ex vivo organ cultures of mucosal explants of healthy donors and Crohn's disease (CD) patients. The extract showed effect in both colitis models reducing the expression of proinflammatory mediators (IL-1ß, TNF-α, and iNOS), and improving the intestinal epithelial barrier integrity restoring the expression of ZO-1, MUC-2, and TFF-3. These effects were confirmed in vitro. Furthermore, it reduced the production of proinflammatory mediators (IL-1ß, IL-6, IL-8, and TNF-α) in intestinal mucosal samples from CD patients. CONCLUSION: Olive leaf extract presented intestinal anti-inflammatory activity in colitis mouse models, maybe be related to its immunomodulatory properties and the capacity to restore the intestinal epithelial barrier. Besides, the extract could also regulate the activity of cells involved in the inflammatory response.

Antiinflammatory and immunomodulatory activity of an ethanolic extract from the stem bark of Terminalia catappa L. (Combretaceae): In vitro and in vivo evidences.

ETHNOPHARMOCOLOGICAL RELEVANCE: Terminalia catappa Linn (Combretaceae) is a medicinal plant with anti-inflammatory, anti-diarrhoeal and antioxidant properties, frequently found in tropical regions. Considering its characteristics, it could be useful for the treatment of inflammatory bowel disease, which is associated with inflammation, oxidative stress and an immune dysfunction. Thus this study evaluates the immunomodulatory properties and the intestinal anti-inflammatory effect of an ethanolic extract of the stem bark of T. catappa (ETCB) both in vitro (in RAW 264.7 macrophages) and in vivo, in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. MATERIALS AND METHODS: The phenolic compounds in ETCB were identified and quantified using HPLC-DAD-qTOF-MS. The immunomodulatory activity ETCB was tested in vitro by determining the macrophage production of IL-1ß and nitrites. In vivo studies were performed in the TNBS model of rat colitis. ETCB was given (25, 50 and 100mg/kg/day) orally for two days prior to colitis induction and thereafter for 7 days. Response to treatment was assessed by scoring the gross appearance of the colon, and determining myeloperoxidase activity, gene expression of pro-inflammatory cytokines like TNF-α, IL-23 and IL-6, chemokines, inducible nitric oxide synthase and proteins crucial in the maintenance of the intestinal mucosal barrier integrity like mucins (MUC-2, MUC-3) and villin. RESULTS: ETCB was able to inhibit IL-1ß and nitrite production in vitro in RAW 264.7 macrophages. Moreover, treatment of TNBS colitic rats with ETCB resulted in a decreased colonic damage score and weight/length ratio. It also reduced the colonic neutrophil infiltration indicated by a lower myeloperoxidase activity and prevented the depletion of colonic glutathione levels in colitic rats. In addition, treatment with ETCB down-regulated the gene expression of pro-inflammatory mediators (TNF-α, IL-23, IL-6 and CINC-1) and iNOS in colitic rats. Moreover, the gene expression of mucosal barrier proteins like MUC-2, MUC-3 and villin were up-regulated in colitic rats treated with ETCB. The dose of ETCB that produced the most significant beneficial effect was 100mg/kg. Regarding the chemical composition of ETCB, 31 phenolic compounds were identified, including ellagic acid, catalagin and gallic acid. CONCLUSION: The beneficial effect of ETCB in the TNBS induced colitis in rats could be related to its antioxidant, immunomodulatory and anti-inflammatory activities, which could be attributed to the phenolic compounds identified.

Anti-inflammatory activity of hydroalcoholic extracts of Lavandula dentata L. and Lavandula stoechas L.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants from genus Lavandula have been used as anti-inflammatory drugs in Mediterranean traditional medicine. Nowadays, there is a growing interest for complementary medicine, including herbal remedies, to treat inflammatory bowel disease (IBD). AIM OF THE STUDY: To test the anti-inflammatory properties of Lavandula dentata and Lavandula stoechas extracts in two inflammatory experimental models: TNBS model of rat colitis and the carrageenan-induced paw edema in mice, in order to mimic the intestinal conditions and the extra-intestinal manifestations of human IBD, respectively. MATERIAL AND METHODS: The extracts were characterized through the qualitative HPLC analysis. Then, they were assayed in vitro and in vivo. In vitro studies were performed in BMDMs and CMT-93 epithelial cells with different concentrations of the extracts (ranging from 0.1 to 100µg/ml). The extracts were tested in vivo in the TNBS model of rat colitis (10 and 25mg/kg) and in the carrageenan-induced paw edema in mice (10, 25 and 100mg/kg). RESULTS: L. dentata and L. stoechas extracts displayed immunomodulatory properties in vitro down-regulating different mediators of inflammation like cytokines and nitric oxide. They also showed anti-inflammatory effects in the TNBS model of colitis as evidenced by reduced myeloperoxidase activity and increased total glutathione content, indicating a decrease of neutrophil infiltration and an improvement of the oxidative state. Besides, both extracts modulated the expression of pro-inflammatory cytokines and chemokines, and ameliorated the altered epithelial barrier function. They also displayed anti-inflammatory effects in the carrageenan-induced paw edema in mice, since a significant reduction of the paw thickness was observed. This was associated with a down-regulation of the expression of different inducible enzymes like MMP-9, iNOS and COX-2 and pro-inflammatory cytokines, all involved in the maintenance of the inflammatory condition. CONCLUSION: L. dentata and L. stoechas extracts showed intestinal anti-inflammatory effect, confirming their potential use as herbal remedies in gastrointestinal disorders. In addition, their anti-inflammatory effect was also observed in other locations, thus suggesting a possible use for the treatment of the extra-intestinal symptoms of IBD.

Intestinal anti-inflammatory effects of oligosaccharides derived from lactulose in the trinitrobenzenesulfonic acid model of rat colitis.

Intestinal microbiota modulation is becoming an interesting approach to manage inflammatory bowel disease and can be achieved by the administration of prebiotics. Previous studies showed the intestinal anti-inflammatory effects of the prebiotic lactulose. The aim of the present study was to test the preventative effects of oligosaccharides derived from lactulose with prebiotic properties (OsLu) in the trinitrobenzenesulfonic acid model of rat colitis and compare them with those of lactulose. Both treatments modified bacterial profile in intestinal contents, increasing the bifidobacteria and lactobacilli counts and up-regulating the production of short-chain fatty acids, although OsLu generated a larger amount. OsLu also inhibited to a greater extent different pro-inflammatory markers such as interleukins (IL) 1, 6, 12, and 23 and chemokines (MCP-1 and CINC-1). However, both prebiotics equally restored colonic epithelial integrity, evaluated both with a histological score (OsLu, 9.8 ± 2.2; and lactulose, 12.1 ± 2.1, vs colitic control, 27.3 ± 3.3) and by measuring several key proteins of the mucosal barrier (MUC-2, MUC-3, and TTF-3). OsLu effect was also associated with an inhibition of iNOS expression and a reduction of Th17 cell activity in the inflamed tissue that facilitated the intestinal mucosa barrier recovery. In conclusion, OsLu showed a better anti-inflammatory profile than lactulose in this model of experimental colitis.

Silk fibroin nanoparticles constitute a vector for controlled release of resveratrol in an experimental model of inflammatory bowel disease in rats.

PURPOSE: We aimed to evaluate the intestinal anti-inflammatory properties of silk fibroin nanoparticles, around 100 nm in size, when loaded with the stilbene compound resveratrol, in an experimental model of rat colitis. METHODS: Nanoparticles were loaded with resveratrol by adsorption. The biological effects of the resveratrol-loaded nanoparticles were tested both in vitro, in a cell culture of RAW 264.7 cells (mouse macrophages), and in vivo, in the trinitrobenzenesulfonic acid model of rat colitis, when administered intracolonically. RESULTS: The resveratrol liberation in 1× phosphate-buffered saline (PBS; pH 7.4) was characterized by fast liberation, reaching the solubility limit in 3 hours, which was maintained over a period of 80 hours. The in vitro assays revealed immunomodulatory properties exerted by these resveratrol-loaded nanoparticles since they promoted macrophage activity in basal conditions and inhibited this activity when stimulated with lipopolysaccharide. The in vivo experiments showed that after evaluation of the macroscopic symptoms, inflammatory markers, and intestinal barrier function, the fibroin nanoparticles loaded with resveratrol had a better effect than the single treatments, being similar to that produced by the glucocorticoid dexamethasone. CONCLUSION: Silk fibroin nanoparticles constitute an attractive strategy for the controlled release of resveratrol, showing immunomodulatory properties and intestinal anti-inflammatory effects.

Intestinal anti-inflammatory activity of hydroalcoholic extracts of Phlomis purpurea L. and Phlomis lychnitis L. in the trinitrobenzenesulphonic acid model of rat colitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Different species from genus Phlomis, frequently native from the the eastern Mediterranean zone, have been used in traditional medicine as an anti-inflammatory remedy. Among other constituents, they contain polyphenols that show antioxidant properties, which are interesting for the treatment of inflammatory pathologies associated with oxidative stress in humans, such as inflammatory bowel disease (IBD). The aim of this study was to evaluate the intestinal anti-inflammatoy effect of hydroalcoholic extracts of Phlomis lychnitis and P. purpurea in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis, a well characterized experimental model with some resemblance to human IBD. MATERIALS AND METHODS: Hydroalcoholic extracts of both plants were characterized by determining their polyphenolic content and then assayed in the TNBS model of rat colitis. For this purpose, female Wistar rats were assigned to seven groups (n=10): healthy control, untreated TNBS-colitis and five TNBS- colitis groups treated with Phlomis lychnitis (10 and 20mg/kg), P. purpurea (10 and 25mg/kg) and sulphasalazine (200mg/kg), as a positive control. Treatments started the same day of TNBS colitis induction, and rats were sacrificed one week later. Colonic inflammation was evaluated both histologically and biochemically. RESULTS: The histological (macroscopic and microscopic) analysis of colonic samples revealed that both extracts showed an anti-inflammatory effect, which was confirmed biochemically by a decreased colonic MPO activity, a maker of neutrophil infiltration, an increased colonic glutathione content, which counteracts the oxidative status associated with the inflammatory process, and a down-regulated iNOS expression. However, only the extract of P. purpurea reduced the expression of the proinflammatory cytokines IL-1ß and IL-17, the chemokines CINC-1 and MCP-1, as well as the adhesion molecule ICAM-1, ameliorating the altered immune response associated with the colonic inflammation. Furthermore, both P. lychnitis and P. purpurea extracts were able to significantly increase the expression of markers of epithelial integrity such as MUC-2, MUC-3 and villin, thus revealing an improvement in the altered colonic permeability that characterizes colonic inflammation. CONCLUSIONS: Both extracts showed intestinal anti-inflammatory activity in the TNBS model of rat colitis, thus confirming their traditional use in digestive inflammatory complaints. In addition to their antioxidant properties, other mechanisms can contribute to this beneficial effect, like an improvement in the intestine epithelial barrier and a downregulation of the immune response.