Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis.

BACKGROUND: Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear. METHODS: The outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing. RESULTS: iMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation. CONCLUSION: Administration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Tigecycline reduces tumorigenesis in colorectal cancer via inhibition of cell proliferation and modulation of immune response.

BACKGROUND: and Purpose: Colorectal cancer (CRC) is one of the cancers with the highest incidence in which APC gene mutations occur in almost 80% of patients. This mutation leads to ß-catenin aberrant accumulation and an uncontrolled proliferation. Apoptosis evasion, changes in the immune response and microbiota composition are also events that arise in CRC. Tetracyclines are drugs with proven antibiotic and immunomodulatory properties that have shown cytotoxic activity against different tumor cell lines. EXPERIMENTAL APPROACH: The effect of tigecycline was evaluated in vitro in HCT116 cells and in vivo in a colitis-associated colorectal cancer (CAC) murine model. 5-fluorouracil was assayed as positive control in both studies. KEY RESULTS: Tigecycline showed an antiproliferative activity targeting the Wnt/ß-catenin pathway and downregulating STAT3. Moreover, tigecycline induced apoptosis through extrinsic, intrinsic and endoplasmic reticulum pathways converging on an increase of CASP7 levels. Furthermore, tigecycline modulated the immune response in CAC, reducing the cancer-associated inflammation through downregulation of cytokines expression. Additionally, tigecycline favored the cytotoxic activity of cytotoxic T lymphocytes (CTLs), one of the main immune defenses against tumor cells. Lastly, the antibiotic reestablished the gut dysbiosis in CAC mice increasing the abundance of bacterial genera and species, such as Akkermansia and Parabacteroides distasonis, that act as protectors against tumor development. These findings resulted in a reduction of the number of tumors and an amelioration of the tumorigenesis process in CAC. CONCLUSION AND IMPLICATIONS: Tigecycline exerts a beneficial effect against CRC supporting the use of this antibiotic for the treatment of this disease.

The Beneficial Effects of Red Sun-Dried Capsicum annuum L. Cv Senise Extract with Antioxidant Properties in Experimental Obesity are Associated with Modulation of the Intestinal Microbiota.

SCOPE: Capsicum annuum L. cv Senise is a sweet pepper containing health promoting compounds that can be modified by ripening and drying. This study focuses on finding the peppers with the best antioxidant properties, which are evaluated on an experimental model of obesity. METHODS AND RESULTS: Phytochemical profile and antioxidant activity are evaluated on several peppers obtained from the same cultivar at different ripening stages. Red sweet peppers show the highest content in polyphenols, ß-carotene, lycopene, and capsinoids, and demonstrate the best antioxidant activity in vitro. Mice fed a high fat diet are orally treated with an extract from these peppers (Capsicum annuum extract [CAE]) (1, 10, and 25 mg/kg/day). It promotes weight loss and improves plasma markers related to glucose and lipid metabolisms. CAE also ameliorates obesity-associated systemic inflammation reducing the expression of pro-inflammatory cytokines in adipose and hepatic tissues and improving the expression of different markers involved in the gut epithelial barrier function. These effects are associated with a modulation of the intestinal microbiome, which appears altered. CONCLUSIONS: The extract can be considered a new potential approach for the treatment of obesity, complementary to dietary restrictions.

Intestinal anti-inflammatory activity of the total alkaloid fraction from Fumaria capreolata in the DSS model of colitis in mice.

Fumaria genus has been traditionally used for managing inflammatory and gastrointestinal disorders. The study evaluates the immunomodulatory potential of the total alkaloid fraction from Fumaria capreolata L. (AFC) in primary macrophages and the intestinal anti-inflammatory effect in a dextran sodium sulphate-induced colitis in mice. AFC inhibited LPS-stimulated bone marrow-derived macrophages gene expression program dose-dependently. In vivo, AFC markedly reduced macroscopic and microscopic signs of intestinal inflammation. Besides, it restored the colonic expression of pro-inflammatory and anti-inflammatory mediators, as well as enhanced the expression of intestinal barrier markers. These results demonstrate the potential of AFC extract as a therapeutic tool for the management of inflammatory bowel disease.

The Beneficial Effects of Lippia Citriodora Extract on Diet-Induced Obesity in Mice Are Associated with Modulation in the Gut Microbiota Composition.

SCOPE: Obesity is characterized by a dysfunction in the adipose tissue and an inflammatory subclinical state leading to insulin resistance and increased risk of cardiovascular diseases. It is also associated with intestinal dysbiosis that contributes to inflammation development. Lippia citriodora (LCE) contains high levels of polyphenolpropanoids and has shown promising results in obesity. The aim of this study is to investigate a well-characterized extract of LCE in a model of metabolic syndrome in mice, focusing on its effects on metabolic tissues, endothelial dysfunction, and microbiome. METHODS: Mice are fed a high fat diet (HFD) for six weeks and treated daily with LCE (1, 10, and 25 mg kg-1 ). Glucose and lipid metabolism is investigated. The inflammatory state in the metabolic tissues and the intestinal microbiota composition are characterized, as well as the endothelium-dependent vasodilator response to acetylcholine. RESULTS: LCE reduces fat accumulation and improves plasma glycemic and lipid profiles, as well as the inflammatory process and vascular dysfunction. Moreover, LCE lessens intestinal dysbiosis, as it reduces the Firmicutes/Bacteroidetes ratio and increases Akkermansia abundance in comparison with untreated HFD mice. CONCLUSION: The antiobesity therapeutic properties of LCE are most probably mediated by the synergic effects of its bioactive compounds.

Intestinal anti-inflammatory effects of goat whey on DNBS-induced colitis in mice.

This study evaluated the intestinal anti-inflammatory effects of goat whey in a mouse model of colitis induced by 2,4-dinitrobenzenesulfonic acid that resembles human IBD. At a concentration of 4 g/kg/day, the goat whey improved the symptoms of intestinal inflammation, namely by decreasing the disease activity index, colonic weight/length, and leukocyte infiltration. Moreover, goat whey inhibited NF-κB p65 and p38 MAPK signaling pathways and consequently down-regulated the gene expression of various proinflammatory markers such as IL-1ß, IL-6, IL-17, TNF-α, iNOS, MMP-9, ICAM-1. Also, goat whey increased the expression of proteins such as mucins, occludin proteins and cytokine signalling suppressors. The immunomodulatory properties of goat whey were also evaluated in vitro using the murine macrophage cell line Raw 264 and CMT-93 cells derived from mouse rectum carcinomas. The results revealed the ability of goat whey to inhibit the production of NO and reduce IL-6 production in LPS-stimulated cells. In conclusion, goat whey exhibited anti-inflammatory effects in the DNBS model of intestinal inflammation, and these observations were confirmed by its immunomodulatory properties in vitro. Together, our results indicate that goat whey could have applications for the treatment of IBD.

Intestinal anti-inflammatory effects of total alkaloid extract from Fumaria capreolata in the DNBS model of mice colitis and intestinal epithelial CMT93 cells.

BACKGROUND: Fumaria capreolata L. (Papaveraceae) is a botanical drug used in North Africa for its gastro-intestinal and anti-inflammatory properties. It is characterized for the presence of several alkaloids that could be responsible for some of its effects, including an immunomodulatory activity. PURPOSE: To test in vivo the intestinal anti-inflammatory properties of the total alkaloid fraction extracted from the aerial parts of F. capreolata (AFC), and to evaluate its effects on an intestinal epithelial cell line. STUDY DESIGN AND METHODS: AFC was chemically characterized by liquid chromatography coupled to diode array detection and high resolution mass spectrometry. Different doses of AFC (25, 50 and 100mg/kg) were assayed in the DNBS model of experimental colitis in mice, and the colonic damage was evaluated both histologically and biochemically. In addition, in vitro experiments were performed with this alkaloid fraction on the mouse intestinal epithelial cell line CMT93 stimulated with LPS. RESULTS: The chemical analysis of AFC revealed the presence of 23 alkaloids, being the most abundants stylopine, protopine and coptisine. Oral administration of AFC produced a significant inhibition of the release and the expression of IL-6 and TNF-α in the colonic tissue. It also suppressed in vivo the transcription of other pro-inflammatory mediators such as IL-1ß, iNOS, IL-12 and IL-17. Furthermore, AFC showed an immunomodulatory effect in vitro since it was able to inhibit the mRNA expression of IL-6, TNF-α and ICAM-1. Moreover, the beneficial effect of AFC in the colitic mice could also be associated with the normalization of the expression of MUC-2 and ZO-1, which are important for the intestinal epithelial integrity. CONCLUSION: The present study suggests that AFC, containing 1.3% of stylopine and 0.9% of protopine, significantly exerted intestinal anti-inflammatory effects in an experimental model of mouse colitis. This fact could be related to a modulation of the intestinal immune response and a restoration of the intestinal epithelial function.

A new therapeutic association to manage relapsing experimental colitis: Doxycycline plus Saccharomyces boulardii.

Immunomodulatory antibiotics have been proposed for the treatment of multifactorial conditions such as inflammatory bowel disease. Probiotics are able to attenuate intestinal inflammation, being considered as safe when chronically administered. The aim of the study was to evaluate the anti-inflammatory effects of doxycycline, a tetracycline with immunomodulatory properties, alone and in association with the probiotic Saccharomyces boulardii CNCMI-745. Doxycycline was assayed both in vitro (Caco-2 epithelial cells and RAW 264.7 macrophages) and in vivo, in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis and the dextran sodium sulfate (DSS) model of mouse colitis. In addition, the anti-inflammatory effect of the association of doxycycline and the probiotic was evaluated in vitro and in vivo in a DSS model of reactivated colitis in mice. Doxycycline displayed immunomodulatory activity in vitro, reducing IL-8 production by intestinal epithelial cells and nitric oxide by macrophages. Doxycycline administration to TNBS-colitic rats (5, 10 and 25 mg/kg) ameliorated the intestinal inflammatory process, being its efficacy comparable to that previously showed by minocycline. Doxycycline treatment was also effective in reducing acute intestinal inflammation in the DSS model of mouse colitis. The association of doxycycline and S. boulardii helped managing colitis in a reactivated model of colitis, by reducing intestinal inflammation and accelerating the recovery and attenuating the relapse. This was evidenced by a reduced disease activity index, colonic tissue damage and expression of inflammatory mediators. This study confirms the intestinal anti-inflammatory activity of doxycycline and supports the potential use of its therapeutic association with S. boulardii for the treatment of inflammatory bowel diseases, in which doxycycline is used to induce remission and long term probiotic administration helps to prevent the relapses.

The probiotic Lactobacillus coryniformis CECT5711 reduces the vascular pro-oxidant and pro-inflammatory status in obese mice.

Obesity is associated with intestine dysbiosis and is characterized by a low-grade inflammatory status, which affects vascular function. In the present study, we evaluated the effects of a probiotic with immunomodulatory properties, Lactobacillus coryniformis CECT5711, in obese mice fed on an HFD (high-fat diet). The probiotic treatment was given for 12 weeks, and it did not affect the weight evolution, although it reduced basal glycaemia and insulin resistance. L. coryniformis administration to HFD-induced obese mice induced marked changes in microbiota composition and reduced the metabolic endotoxaemia as it decreased the LPS (lipopolysaccharide) plasma level, which was associated with a significant improvement in gut barrier disruption. Furthermore, it lowered TNFα (tumour necrosis factor α) expression in liver, improving the inflammatory status, and thus the glucose metabolism. Additionally, the probiotic reversed the endothelial dysfunction observed in obese mice when endothelium- and NO (nitric oxide)-dependent vasodilatation induced by acetylcholine in aortic rings was studied. It also restored the increased vessel superoxide levels observed in obese mice, by reducing NADPH oxidase activity and increasing antioxidant enzymes. Moreover, chronic probiotic administration for 2 weeks also improved endothelial dysfunction and vascular oxidative stress induced by in vivo administration of LPS in control mice fed on a standard chow diet. The results of the present study demonstrate an endothelial-protective effect of L. coryniformis CECT5711 in obese mice by increasing NO bioavailability, suggesting the therapeutic potential of this gut microbiota manipulation to prevent vasculopathy in obesity.

The immunomodulatory properties of viable Lactobacillus salivarius ssp. salivarius CECT5713 are not restricted to the large intestine.

PURPOSE: The aim of this study was to better characterise the biological effects of Lactobacillus salivarius ssp. salivarius CECT5713, a probiotic with immunomodulatory properties. METHODS: Live or dead probiotic was assayed in the TNBS model of rat colitis to determine whether viability was a requisite to exert the beneficial effects. In vitro studies were also performed in Caco-2 cells to evaluate its effects on epithelial cell recovery and IL-8 production. Finally, the probiotic was assayed in the LPS model of septic shock in mice to establish its effects when there is an altered systemic immune response. RESULTS: The viability of the probiotic was required for its anti-inflammatory activity. The probiotic inhibited IL-8 production in stimulated Caco-2 cells and facilitated the recovery of damaged intestinal epithelium. In LPS-treated mice, the probiotic inhibited the production of TNFα in plasma and lungs and increased the hepatic glutathione content. These effects were associated with an improvement in the altered production of the T-cell cytokines in splenocytes, by reducing IL-2 and IL-5 and by increasing IL-10. Finally, it reduced the increased plasma IgG production in LPS-treated mice. CONCLUSION: The anti-inflammatory effects of viable L. salivarius ssp. salivarius CECT5713 are not restricted to the gastrointestinal tract.

The intestinal anti-inflammatory effect of minocycline in experimental colitis involves both its immunomodulatory and antimicrobial properties.

Some antibiotics, including minocycline, have recently been reported to display immunomodulatory properties in addition to their antimicrobial activity. The use of a compound with both immunomodulatory and antibacterial properties could be very interesting in the treatment of inflammatory bowel disease (IBD), so the aim of our study was to evaluate the anti-inflammatory effect of minocycline in several experimental models of IBD. Firstly, the immunomodulatory activity of the antibiotic was tested in vitro using Caco-2 intestinal epithelial cells and RAW 264.7 macrophages; minocycline was able to inhibit IL-8 and nitrite production, respectively. In vivo studies were performed in trinitrobenzenesulfonic acid (TNBS)-induced rat colitis and dextran sodium sulfate (DSS)-induced mouse colitis. The results revealed that minocycline exerted an intestinal anti-inflammatory effect when administered as a curative treatment in the TNBS model, modulating both immune and microbiological parameters, being confirmed in the DSS model; whereas none of the other antibiotics tested (tetracycline and metronidazole) showed anti-inflammatory effect. However, minocycline administration before the colitis induction was not able to prevent the development of the intestinal inflammation, thus showing that only its antimicrobial activity is not enough for the anti-inflammatory effect. In conclusion, minocycline displays an anti-inflammatory effect on different models of rodent colitis which could be attributed to the association of its antibacterial and immunomodulatory properties.

Di-D-fructose dianhydride-enriched caramels: effect on colon microbiota, inflammation, and tissue damage in trinitrobenzenesulfonic acid-induced colitic rats.

In the present study we describe the preparation and chemical characterization of a caramel with a high (70%) content of difructose dianhydrides (DFAs) and glycosylated derivatives (DFAs). This product was obtained by thermal activation (90 degrees C) of highly concentrated (90% w/v) aqueous D-fructose solutions using the sulfonic acid ion-exchange resin Lewatit S2328 as caramelization catalyst. DFAs represent a unique family of cyclic fructans with prebiotic properties already present in low proportions (<15%) in commercial caramel. We report the antiinflammatory activity of the new DFA-enriched caramel in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, an experimental model that resembles human inflammatory bowel disease (IBD), and compare its effects with those obtained with a commercial sucrose caramel and with linear fructooligosaccharides (FOS). For this purpose, the effects on colon tissue damage, gut microbiota, short-chain fatty acid (SCFAs) production, and different inflammatory markers were evaluated. The administration of DFA-enriched caramel to colitic rats showed intestinal antiinflammatory effect, as evidenced macroscopically by a significant reduction in the extent of the colonic damage induced by TNBS. This effect was similar to that obtained with FOS in the same experimental settings, whereas commercial caramel was devoid of any significant antiinflammatory effect. The beneficial effect was associated with the inhibition of the colonic levels of the proinflammatory cytokines, tumor necrosis factor alpha (TNF alpha) and interleukin 1beta (IL-1beta), and the reduction in colonic myeloperoxidase (MPO) activity and inducible nitric oxide synthase (iNOS) expression. The DFA-enriched caramel also promoted a more favorable intestinal microbiota, increasing lactobacilli and bifidobacteria counts as well as inducing higher concentrations of SCFAs in the luminal colonic contents. These results reinforce the concept of DFAs and glycosyl-DFAs as dietary beneficial compounds with prebiotic properties and suggest that the novel DFA-enriched caramel here reported may be an interesting candidate to be explored for the dietary treatment of human IBD.

Butyrate in vitro immune-modulatory effects might be mediated through a proliferation-related induction of apoptosis.

Survival and proliferation signals are two processes closely interrelated and finely controlled in most cell types, whose deregulation may lead to carcinogenesis. In the last decade, different studies have suggested that both cellular functions are also intimately associated with other cellular activities such as differentiation and cellular activation, especially in immune cells. The aim of this study was to evaluate the effects of the short-chain fatty acid (SCFA) butyrate on the proliferation and activation state of different cell types involved in inflammatory bowel disease. We focused on intestinal epithelial cells, macrophages and T-lymphocytes, using both primary non-transformed cultures and established cell lines. The results showed that low concentrations of butyrate inhibited the proliferation of all the immune cell types tested in this work, whereas it only induced apoptosis in activated T-lymphocytes, non-differentiated epithelial cells and macrophage cell lines, but not in differentiated epithelial cells or primary macrophages. Butyrate apoptosis induction was mediated by caspase-3/7 activation. This SCFA was only able to modify cell activation, measured as expression of inflammatory cytokines, in those cell types in which apoptosis was induced. In conclusion, our results suggest a cell type-specificity of the immune-modulatory effects of butyrate based on the proliferation/activation characteristic physiology of these processes in different cells types.

Evaluation of the preventative effects exerted by Lactobacillus fermentum in an experimental model of septic shock induced in mice.

The preventative effects of the probiotic Lactobacillus fermentum CECT5716 were evaluated in the lipopolysaccharide (LPS) model of septic shock in mice. The probiotic was administered suspended in drinking water at the final concentration of 108 colony-forming units/ml for 2 weeks before the induction of an endotoxic shock by an intraperitoneal injection of LPS (400 microg/200 microl per mouse). Blood and different organs were collected after 24 h to evaluate the severity of the endotoxic shock and the preventative effects of the probiotic. L. fermentum reduced TNF-alpha levels in blood, which promotes the major alterations observed during septic shock, as well as the infiltration of activated neutrophils into the lungs. Furthermore, free radical overproduction and oxidative stress were associated with a significant decrease in hepatic glutathione levels in septic mice, and with an excessive NO production attributed to the induction of the inducible isoform of NO synthase (iNOS). In fact, hepatic glutathione levels were significantly increased in the group of mice receiving the probiotic, and the increased iNOS expression both in the colon and lungs was down-regulated in those mice treated with L. fermentum. Finally, pre-treatment with L. fermentum may also exert its protective action modulating the expression of different cytokines in splenocyte-derived T cells such us IL-2, IL-5, IL-6 or IL-10. In conclusion, pre-treatment with L. fermentum may exert its protective action against LPS-induced organ damage in mice by a combination of several actions including its antioxidant properties and by reduction of the synthesis of the pro-inflammatory TNF-alpha and IL-6.

The intestinal anti-inflammatory activity of UR-12746S on reactivated experimental colitis is mediated through downregulation of cytokine production.

BACKGROUND: UR-12746S (dersalazine sodium) is cleaved by colonic bacteria delivering the PAF antagonist UR-12715 and 5-ASA. This study describes the anti-inflammatory activity of UR-12746S in an experimental model of reactivated colitis and its effects on cytokine production. METHODS: Rats were initially rendered colitic by a colonic instillation of 10 mg of trinitrobenzenesulphonic acid (TNBS) dissolved in 0.25 ml of 50 % ethanol, and colitis was reactivated two weeks after by a second administration of the same dose of TNBS. Two groups of colitic rats received UR-12746S (25 and 50 mg/kg daily, p.o.) and colonic damage was evaluated every week for 4 weeks. Different biochemical markers of colonic inflammation were assayed: MPO activity and cytokine (IL-1beta and TNFalpha) levels. Also, the in vitro effects of UR-12715 and 5-ASA on cytokine production were assayed. RESULTS: UR-12746S showed anti-inflammatory effect in reactivated colitis in rats, as evidenced by a significant reduction in MPO activity. Both doses of UR-12746S decreased IL-1beta production, while only the highest dose assayed inhibited TNFalpha production. In vitro studies revealed that UR-12715 or 5-ASA (from 10(-6) to 10(-4) M) inhibited IL-8 production (30-40%) in HT-29 cells when incubated with LPS. This inhibitory effect was enhanced when both compounds were administered simultaneously at 10(-4) M. In addition, UR-12715 inhibited IL-1beta or TNFalpha production in THP-1 or U937 cells, respectively, when these cells were stimulated by PMA and LPS; whereas 5-ASA only showed a weak effect in inhibiting IL-1beta production. CONCLUSION: UR-12746S was able to prevent relapse in experimental colitis and inhibition of proinflammatory cytokine production participates in the intestinal anti-inflammatory activity exerted by this compound.

Dietary fiber down-regulates colonic tumor necrosis factor alpha and nitric oxide production in trinitrobenzenesulfonic acid-induced colitic rats.

Previous studies have revealed the beneficial effects exerted by dietary fiber in human inflammatory bowel disease, which were associated with an increased production of SCFA in distal colon. The aim of the present study was to elucidate the probable mechanisms involved in the beneficial effects of a fiber-supplemented diet (5% Plantago ovata seeds) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, with special attention to its effects on the production of some of the mediators involved in the inflammatory response, such as tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the fiber-supplemented diet for 2 wk before TNBS colitis induction and thereafter until colonic evaluation 1 wk later. The results obtained showed that dietary fiber supplementation facilitated recovery from intestinal insult as evidenced both histologically, by a preservation of intestinal cytoarchitecture, and biochemically, by a significant reduction in colonic myeloperoxidase activity and by restoration of colonic glutathione levels. This intestinal anti-inflammatory effect was associated with lower TNFalpha levels and lower NO synthase activity in the inflamed colon, showing significant differences when compared with nontreated colitic rats. Moreover, the intestinal contents from fiber-treated colitic rats showed a significantly higher production of SCFA, mainly butyrate and propionate. We conclude that the increased production of these SCFA may contribute to recovery of damaged colonic mucosa because they constitute substrates for the colonocyte and, additionally, that they can inhibit the production of proinflammatory mediators, such as TNFalpha and NO.