Lack of mTORC2 signaling in CD11c+ myeloid cells inhibits their migration and ameliorates experimental colitis.

The mammalian target of rapamycin (mTOR) pathway plays a key role in determining immune cells function through modulation of their metabolic status. By specific deletion of Rictor in CD11c+ myeloid cells (referred to here as CD11cRicΔ/Δ), we investigated the role of mTOR complex 2 (mTORC2) signaling in dendritic cells (DCs) function in mice. We showed that upon dextran sulfate sodium-induced colitis, the lack of mTORC2 signaling CD11c+ cells diminishes the colitis score and abrogates DC migration to the mesenteric lymph nodes, thereby diminishing the infiltration of T helper 17 cells in the lamina propria and subsequent inflammation. These findings corroborate with the abrogation of cytoskeleton organization and the decreased activation of Rac1 and Cdc42 GTPases observed in CD11c+-mTORC2-deficient cells. Meta-analysis on colonic samples from ulcerative colitis patients revealed increased gene expression of proinflammatory cytokines, which coincided with augmented expression of the mTOR pathway, a positive correlation between the DC marker ITGAX and interleukin-6, the expression of RICTOR, and CDC42. Together, this work proposes that targeting mTORC2 on DCs offers a key to hamper inflammatory responses, and this way, ameliorates the progression and severity of intestinal inflammatory diseases.

Perineuronal net in the extrinsic innervation of the distal colon of mice and its remodeling in ulcerative colitis.

The perineuronal net (PNN) is a well-described highly specialized extracellular matrix structure found in the central nervous system. Thus far, no reports of its presence or connection to pathological processes have been described in the peripheral nervous system. Our study demonstrates the presence of a PNN in the spinal afferent innervation of the distal colon of mice and characterizes structural and morphological alterations induced in an ulcerative colitis (UC) model. C57Bl/6 mice were given 3% dextran sulfate sodium (DSS) to induce acute or chronic UC. L6/S1 dorsal root ganglia (DRG) were collected. PNNs were labeled using fluorescein-conjugated Wisteria Floribunda (WFA) l lectin, and calcitonin gene-related peptide (CGRP) immunofluorescence was used to detect DRG neurons. Most DRG cell bodies and their extensions toward peripheral nerves were found surrounded by the PNN-like structure (WFA+), labeling neurons' cytoplasm and the pericellular surfaces. The amount of WFA+ neuronal cell bodies was increased in both acute and chronic UC, and the PNN-like structure around cell bodies was thicker in UC groups. In conclusion, a PNN-like structure around DRG neuronal cell bodies was described and found modulated by UC, as changes in quantity, morphology, and expression profile of the PNN were detected, suggesting a potential role in sensory neuron peripheral sensitization, possibly modulating the pain profile of ulcerative colitis.

Orange juice containing Pediococcus acidilactici CE51 modulates the intestinal microbiota and reduces induced inflammation in a murine model of colitis.

The management of inflammatory bowel diseases has been widely investigated, especially ulcerative colitis. Thus, studies with the application of new probiotic products are needed in the prevention/treatment of these clinical conditions. The objective of this work was to evaluate the effects of probiotic orange juice containing Pediococcus acidilactici CE51 in a murine model of colitis. 45 male Swiss lineage mice were used, divided into five groups (n = 9): control, colitis, colitis + probiotic (probiotic orange juice containing CE51), colitis + placebo (orange juice) and colitis + sulfasalazine (10 mg/kg/Weight). The induction of colitis was performed with dextran sodium sulfate (3%). The treatment time was 5 and 15 days after induction. Histopathological analysis, serum measurements of TNF-α and C-reactive protein and metagenomic analysis of feces were performed after euthanasia. Probiotic treatment reduced inflammation in the small intestine, large intestine and spleen. The probiotic did not alter the serum dosages of TNF-α and C-reactive protein. Their use maintained the quantitative ratio of the phylum Firmicutes/Bacteroidetes and increased Lactobacillus helveticus with 15 days of treatment (p < 0.05). The probiotic orange juice containing P. acidilactici CE51 positively modulated the gut microbiota composition and attenuated the inflammation induced in colitis.

Extraintestinal Manifestations in Induced Colitis: Controversial Effects of N-Acetylcysteine on Colon, Liver, and Kidney.

Ulcerative colitis (UC) is a chronic and recurrent inflammatory bowel disease (IBD) characterized by continuous inflammation in the colonic mucosa. Extraintestinal manifestations (EIM) occur due to the disruption of the intestinal barrier and increased permeability caused by redox imbalance, dysbiosis, and inflammation originating from the intestine and contribute to morbidity and mortality. The aim of this study is to investigate the effects of oral N-acetylcysteine (NAC) on colonic, hepatic, and renal tissues in mice with colitis induced by dextran sulfate sodium (DSS). Male Swiss mice received NAC (150 mg/kg/day) in the drinking water for 30 days before and during (DSS 5% v/v; for 7 days) colitis induction. On the 38th day, colon, liver, and kidney were collected and adequately prepared for the analysis of oxidative stress (superoxide dismutase (SOD), catalase (CAT), glutathione reduced (GSH), glutathione oxidized (GSSG), malondialdehyde (MDA), and hydrogen peroxide (H2O2)) and inflammatory biomarkers (myeloperoxidase (MPO) -, tumor necrosis factor alpha - (TNF-α, and interleukin-10 (IL-10)). In colon, NAC protected the histological architecture. However, NAC did not level up SOD, in contrast, it increased MDA and pro-inflammatory effect (increased of TNF-α and decreased of IL-10). In liver, colitis caused both oxidative (MDA, SOD, and GSH) and inflammatory damage (IL-10). NAC was able only to increase GSH and GSH/GSSG ratio. Kidney was not affected by colitis; however, NAC despite increasing CAT, GSH, and GSH/GSSG ratio promoted lipid peroxidation (increased MDA) and pro-inflammatory action (decreased IL-10). Despite some beneficial antioxidant effects of NAC, the negative outcomes concerning irreversible oxidative and inflammatory damage in the colon, liver, and kidney confirm the nonsafety of the prophylactic use of this antioxidant in models of induced colitis, suggesting that additional studies are needed, and its use in humans not yet recommended for the therapeutic routine of this disease.

Effects of Mimosa caesalpiniifolia pre-formulation on the intestinal barrier during sodium dextran sulfate-induced colitis in Wistar rats / Efectos de la preformulación de Mimosa caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico en ratas Wistar

INTRODUCTION: Anti-inflammatories, immunosuppressants, and immunobiological are commonly used in the treatment of inflammatory bowel disease. However, some patients do not present an adequate response or lose effective response during the treatment. A recent study found a potential anti-inflammatory effect of the hydroalcoholic extract of Mimosa caesalpiniifolia on trinitrobenzene sulfonic acid-induced colitis in Wistar rats. OBJECTIVE: To evaluate the effects of M. caesalpiniifolia pre-formulation on the intestinal barrier using dextran sulfate sodium-induced colitis model. MATERIALS AND METHODS: Leaf extracts were prepared in 70% ethanol and dried with a Buchi B19 Mini-spray dryer using 20% Aerosil® solution. Thirty-two male Wistar rats were randomized into four groups: basal control, untreated colitis, pre-formulation control (125 mg/kg/day), and colitis treated with pre-formulation (125 mg/kg/day). Clinical activity index was recorded daily and all rats were euthanized on the ninth day. Colon fragments were fixed and processed for histological and ultrastructural analyses. Stool samples were collected and processed for analysis of the short-chain fatty acid. RESULTS: Treatment with the pre-formulation decreased the clinical activity (bloody diarrhea), inflammatory infiltrate, and the ulcers. Pre-formulation did not repair the epithelial barrier and there were no significant differences in the goblet cells index. There was a significant difference in butyrate levels in the rats treated with the pre-formulation. CONCLUSIONS: The pre-formulation minimized the clinical symptoms of colitis and intestinal inflammation, but did not minimize damage to the intestinal barrier.

Introducción: Los antiinflamatorios, inmunosupresores e inmunobiológicos se utilizan comúnmente para tratar la enfermedad intestinal inflamatoria. Sin embargo, algunos pacientes no presentan una respuesta adecuada o pierden respuesta efectiva durante el tratamiento. En un estudio reciente, se encontró un potencial efecto antiinflamatorio del extracto hidroalcohólico de Mimosa caesalpiniifolia en la colitis inducida por el ácido trinitrobenceno sulfónico utilizando ratas Wistar. Objetivo: Evaluar los efectos de la preformulación de M. caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico. Materiales y métodos: Los extractos de hojas se prepararon con una solución que contenía 70 % de etanol y se secaron con un secador por aspersión Mini B19 de Buchi usando una solución con 20 % de Aerosil®. Treinta y dos ratas Wistar macho se aleatorizaron en cuatro grupos: control basal, colitis sin tratar, control con preformulación (125 mg/kg/día) y colitis tratada con preformulación (125 mg/kg/día). El índice de actividad clínica se registró diariamente y todas las ratas se sacrificaron el noveno día. Los fragmentos de colon se fijaron y se procesaron para análisis histológicos y ultraestructurales. Se recolectaron muestras de heces y se procesaron para el análisis de ácidos grasos de cadena corta. Resultados: El tratamiento con la preformulación disminuyó la actividad clínica (diarrea sanguinolenta), el infiltrado inflamatorio y las úlceras. La preformulación no reparó la barrera epitelial y no hubo diferencias significativas en el índice de células caliciformes. Se obtuvo una diferencia significativa en los niveles de butirato en las ratas tratadas con la preformulación. Conclusiones: La preformulación minimizó los síntomas clínicos de colitis e inflamación intestinal pero no minimizó el daño a la barrera intestinal.

Colonic motility adjustments in acute and chronic DSS-induced colitis.

AIMS: Inflammatory bowel disease is recurrent inflammation that affects the gastrointestinal tract causing changes in intestinal motility. The evolution of these changes is not completely understood. The aim of this study was to evaluate anatomical and functional changes in the colon during the development of acute and chronic DSS-induced ulcerative colitis (UC) in C57Bl/6 mice. MATERIALS AND METHODS: Mice were relocated into 5 groups: control (GC) and groups exposed to DSS 3 % for 2 (DSS2d), 5 (DSS5d) and 7 DSS7d) days (acute UC) or 3 cycles (DSS3C; Chronic UC). Mice were monitored daily. After euthanasia, colonic tissue was assessed with histological, immunofluorescence and colon manometry methods. KEY FINDINGS: Ulcerative Colitis is a chronic disease characterized by overt inflammation of the colon. Here we investigate whether the morphological changes caused by UC in the colonic wall, in tuft cells and in enteric neurons also promote any alteration in colonic motility patterns. UC Promotes thickening in the colonic wall, fibrosis, reduction in the number of tuft cells and consequently goblet cells also, without promoting neuronal death however there is a change in the chemical code of myenteric neurons. All of these morphological changes were responsible for causing a change in colonic contractions, colonic migration motor complex, total time of gastrointestinal transit and therefore promoting dysmotility. Further studies stimulating a hyperplasia of tuft cells may be the way to try to keep the colonic epithelium healthy, reducing the damage caused by UC. SIGNIFICANCE: Increasing disease pathology of DSS-induced UC induces structural and neuroanatomical changes and driven damage to cholinergic neurons causes colonic dysmotility, including increase of cholinergic myenteric neurons, followed by variations in the motility pattern of different regions of the colon that taking together characterize colonic dysmotility.

Protective Effect of Dietary Polysaccharides from Yellow Passion Fruit Peel on DSS-Induced Colitis in Mice.

Inflammatory bowel disease (IBD) is a complex inflammatory disorder characterized by chronic and spontaneously relapsing inflammation of the gastrointestinal tract. IBD includes two idiopathic disorders: Crohn's disease (CD) and ulcerative colitis (UC). In particular, UC causes inflammation and ulceration of the colon and rectum. There is no cure for UC. The pharmacological treatment is aimed at controlling and/or reducing the inflammatory process and promoting disease remission. The present study investigated the possible protective effects of soluble dietary fiber (SDF) isolated from yellow passion fruit peel in the dextran sulfate sodium- (DSS-) induced colitis model in mice, induced by 5% of DSS. The animals were treated with SDF (10, 30, or 100 mg/kg (po)), and the disease activity index was monitored. Colon tissues were collected, measured, and prepared for oxidative stress, inflammation, and histology analysis. SDF improved body weight loss, colon length, and disease activity index and prevented colonic oxidative stress by regulating GSH levels and SOD activity. Furthermore, SDF reduced colonic MPO activity, TNF-α, and IL-1ß levels and increased IL-10 and IL-6 levels. As observed by histological analysis, SDF treatment preserved the colonic tissue, the mucus barrier, and reduced inflammatory cell infiltration. Although this is a preliminary study, taken together, our data indicate that SDF may improve the course of DSS-UC. More studies are needed to explore and understand how SDF promotes this protection.

Peroxisome Proliferator-Activated Receptor Alpha Mediates the Beneficial Effects of Atorvastatin in Experimental Colitis.

The current therapeutic options for Inflammatory Bowel Diseases (IBD) are limited. Even using common anti-inflammatory, immunosuppressive or biological therapies, many patients become unresponsive to the treatments, immunosuppressed or unable to restrain secondary infections. Statins are cholesterol-lowering drugs with non-canonical anti-inflammatory properties, whose underlying mechanisms of action still remain poorly understood. Here, we described that in vitro atorvastatin (ATO) treatment was not toxic to splenocytes, constrained cell proliferation and modulated IL-6 and IL-10 production in a dose-dependent manner. Mice exposed to dextran sulfate sodium (DSS) for colitis induction and treated with ATO shifted their immune response from Th17 towards Th2, improved the clinical and histological aspects of intestinal inflammation and reduced the number of circulating leukocytes. Both experimental and in silico analyses revealed that PPAR-α expression is reduced in experimental colitis, which was reversed by ATO treatment. While IBD patients also downregulate PPAR-α expression, the responsiveness to biological therapy relied on the restoration of PPAR-α levels. Indeed, the in vitro and in vivo effects induced by ATO treatment were abrogated in Ppara-/- mice or leukocytes. In conclusion, the beneficial effects of ATO in colitis are dependent on PPAR-α, which could also be a potential predictive biomarker of therapy responsiveness in IBD.

Lactobacillus bulgaricus inhibits colitis-associated cancer via a negative regulation of intestinal inflammation in azoxymethane/dextran sodium sulfate model.

BACKGROUND: Colitis-associated cancer (CAC) accounts for 2%-3% of colorectal cancer (CRC) cases preceded by inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis. Intestinal microbiota has been reported to play a central role in the pathogenesis of IBD and CAC. Recently, numerous prebiotics and probiotics have being investigated as antitumor agents due to their capacity to modulate inflammatory responses. Previous studies have indicated that lactic acid bacteria could be successfully used in managing sporadic CRC, however little is known about their role in CAC. AIM: To investigate the effect of the probiotic Lactobacillus bulgaricus (L. bulgaricus) during the development of an experimental model of colitis associated colon cancer (CAC). METHODS: C57BL/6 mice received an intraperitoneal injection of azoxymethane (10 mg/kg), followed by three cycles of sodium dextran sulphate diluted in water (5% w/v). Probiotic group received daily L. bulgaricus. Intestinal inflammation was determined by scoring clinical signs. Cytokines levels were determined from colon and/or tumor samples by ELISA BD OptEIATM kits. The level of significance was set at P < 0.05. Graphs were generated and statistical analysis performed using the software GraphPad Prism 6.0. RESULTS: L. bulgaricus treatment inhibited of total tumor volume and mean size of tumors. In addition, the probiotic also attenuated the clinical signs of intestinal inflammation inducing a decrease in intestinal and tumor levels of IL-6, TNF-α, IL-17, IL-23 and IL-1ß. CONCLUSION: Our results suggest a potential chemopreventive effect of probiotic on CAC. L. bulgaricus regulates the inflammatory response and preventing CAC.

Beneficial effects resulting from oral administration of Escherichia coli Nissle 1917 on a chronic colitis model.

Inflammatory bowel diseases (IBD) are chronic processes involving a deregulated immune response against intestinal microbiota in genetically susceptible individuals. Ulcerative colitis (UC) is an IBD restricted to colonic mucosa and its chronicity is a predisposing factor for colorectal cancer (CRC). Probiotics have been investigated as an adjuvant treatment for UC, and Escherichia coli Nissle 1917 (EcN) was the focus of our investigation. The aim of this study was to investigate the preventive effect of the EcN probiotic in an experimental model of chronic colitis in germ-free (GF) and conventional (CV) mice. CV female mice were used for clinical, immunological and permeability experiments. GF mice were used for a faecal microbiota transplantation assay. To induce colitis, three cycles of 3.0% dextran sulphate sodium (DSS) were administered to the animals. For probiotic treatment, the mice received a daily intragastric gavage of 9.0 log10 cfu of EcN, beginning 10 days before colitis induction and continuing until the end of the experiment. EcN presented beneficial effects when administered preventively. Daily Disease Activity Index (DAI) evolution demonstrated significant difference in remission periods after the first two DSS cycles and during the third one. Reduction in bacterial translocation after probiotic treatment indicated protection of the intestinal barrier. Associated with mucosal preservation, restoration of secretory immunoglobulin A levels and reduction of interleukin (IL)-5, IL-13, tumour necrosis factor and interferon-γ levels were observed in EcN treatment. Finally, when microbiota modification was verified, 16S rRNA-based compositional analysis showed variation of intestinal microbiota between the control and colitis groups. After faecal transplantation using GF mice, it was observed that EcN treatment in CV mice might result in modulated intestinal microbiota. This was observed indirectly in the reduced daily DAI, when colitis was compared with treated group. In conclusion, EcN presented beneficial effects in this model, suggesting its usefulness for treating UC.

Extra virgin olive oil and flaxseed oil have no preventive effects on DSS-induced acute ulcerative colitis.

OBJECTIVES: The aim of this study was to evaluate the preventive effects of extra virgin olive oil (EVOO) or flaxseed oil (FO) on dextran sodium sulfate (DSS)-induced acute ulcerative colitis in female mice. METHODS: Eighty C57BL/6J mice of 8-weeks-old were divided in four groups: Control (SO), 10%EVOO, 10%FO and 5%EVOO+5%FO. The oils were given through the AIN-93M diet. After 30 days, animals were divided in four more groups, in which half received 3%DSS in water for 5 days. Body weight loss, bleeding and stool consistency were verified for the Disease Activity Index (DAI). Animals were euthanized and their colon and spleen weighted and measured. Histopathological analysis, the concentrations of TNF-α, IL-1ß, and IL-10 and the iNOS expression were evaluated in the colon samples. RESULTS: Animals that received DSS presented with elevated disease activity index values; increased colon weight-to-length ratio; augmented leukocyte infiltration into the lamina propria and submucosa; and increased production of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-6, and greater inducible nitric oxide synthase expression in the distal colon. Individually or in combination, the oils were not able to reverse or mitigate any of the DSS-induced symptoms or damage. Additionally, the group of animals treated with DSS and supplemented with FO displayed increased spleen weight-to-body weight ratio, and the group that received a combination of EVOO and FO presented increased TNF-α levels compared with the respective control group. CONCLUSION: Consumption of large amounts of EVOO and FO as a treatment for or prevention against ulcerative colitis could potentially elicit unwanted adverse effects.

Treatment with a Zinc Metalloprotease Purified from Bothrops moojeni Snake Venom (BmooMP-Alpha-I) Reduces the Inflammation in an Experimental Model of Dextran Sulfate Sodium-Induced Colitis.

It has been described that the metalloprotease BmooMP-alpha-I purified from Bothrops moojeni snake venom is able to hydrolyze the TNF molecule. However, this observation has been based mainly on in vitro investigation, in addition to molecular modeling and docking approaches. Considering that there is no in vivo study to demonstrate the biological effects of this enzyme, the major aim to the present work was to investigate whether the BmooMP-alpha-I has any anti-inflammatory efficacy by setting up a murine experimental design of colitis induced by dextran sulfate sodium (DSS). For this purpose, C57BL/6 mice were divided into six groups, as follows: (i) animals without intestinal inflammation, (ii) animals without intestinal inflammation treated with BmooMP-alpha-I (50 µg/animal/day), and (iii) animals with intestinal inflammation induced by 3% of DSS, (iv) mice with intestinal inflammation induced by DSS and treated with BmooMP-alpha-I enzyme at the 50, 25, or 12.5 µg/animal/day dosages by intraperitoneal route. Clinical signs of colitis were observed daily for calculating the morbidity scores, cytokine measurements, and histological features. We observed that the animals treated with different doses of the enzyme presented a remarkable improvement of colitis signs, as confirmed by a significant increase of the intestine length in comparison to the DSS group. Also, no difference was observed between the groups treated with the enzyme or vehicle, as the colon length of these animals was slightly lower than that of the group of healthy animals, without induction of intestinal inflammation. The cytokine quantification in supernatants of intestinal tissue homogenates showed a significant reduction of 38% in IFN-gamma levels, when the animals were treated with 50 µg of the BmooMP-alpha-I compared to the animals receiving DSS only. A significant reduction of 39% in TNF levels was also observed in all doses of treatment with BmooMP-alpha-I, in addition to a significant reduction of 35% in the amount of IL-12p40. Histological examinations revealed that the BmooMP-alpha-I 50 µg treated group preserved colon architecture and goblet cells and reduced the ulcer area, when compared with DSS mice, which showed typical inflammatory changes in tissue architecture, such as ulceration, crypt dilation, loss of tissue architecture, and goblet cell depletion, accompanied by a significant cell infiltration. In conclusion, our results suggest that the improvement of clinical scores and histological findings related to BmooMP-alpha-I treatment in this experimental model could be attributed to the metalloprotease ability to modulate cytokine production locally at the inflamed intestine. These findings highlight the potential anti-inflammatory role and effectiveness of this enzyme as a therapeutic alternative in this type of immunopathological condition.

Beneficial effects of nutritional supplements on intestinal epithelial barrier functions in experimental colitis models in vivo.

Acute and chronic colitis affect a huge proportion of the population world-wide. The etiology of colitis cases can be manifold, and diet can significantly affect onset and outcome of colitis. While many forms of acute colitis are easily treatable, chronic forms of colitis such as ulcerative colitis and Crohn's disease (summarized as inflammatory bowel diseases) are multifactorial with poorly understood pathogenesis. Inflammatory bowel diseases are characterized by exacerbated immune responses causing epithelial dysfunction and bacterial translocation. There is no cure and therapies aim at reducing inflammation and restoring intestinal barrier function. Unfortunately, most drugs can have severe side effects. Changes in diet and inclusion of nutritional supplements have been extensively studied in cell culture and animal models, and some supplements have shown promising results in clinical studies. Most of these nutritional supplements including vitamins, fatty acids and phytochemicals reduce oxidative stress and inflammation and have shown beneficial effects during experimental colitis in rodents induced by dextran sulphate sodium or 2,4,6-trinitrobenzene sulfonic acid, which remain the gold standard in pre-clinical colitis research. Here, we summarize the mechanisms through which such nutritional supplements contribute to epithelial barrier stabilization.

Homoectoine Protects Against Colitis by Preventing a Claudin Switch in Epithelial Tight Junctions.

BACKGROUND: Inflammatory bowel diseases (IBD) are multifactorial disorders affecting millions of people worldwide with alarmingly increasing incidences every year. Dysfunction of the intestinal epithelial barrier is associated with IBD pathogenesis, and therapies include anti-inflammatory drugs that enhance intestinal barrier function. However, these drugs often have adverse side effects thus warranting the search for alternatives. Compatible solutes such as bacterial ectoines stabilize cell membranes and proteins. AIM: To unravel whether ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) and homoectoine (4,5,6,7-tetrahydro-2-methyl-1H-(1,3)-diazepine-4-carboxylic acid), a synthetic derivative of ectoine, have beneficial effects during dextran sulfate sodium (DSS)-induced colitis in mice. METHODS/RESULTS: We found that the disease activity index was significantly reduced by both ectoines. DSS-induced edema formation, epithelial permeability, leukocyte recruitment and tissue damage were reduced by ectoine and homoectoine, with the latter having stronger effects. Interestingly, the claudin switch usually observed during colitis (decreased expression of claudin-1 and increased expression of the leaky claudin-2) was completely prevented by homoectoine, whereas ectoine only reduced claudin-2 expression. Concomitantly, only homoectoine ameliorated the drop in transepithelial electrical resistance induced by IFN-γ and TNF-α in Caco-2 cells. Both ectoines inhibited loss of ZO-1 and occludin and prevented IFN-γ/TNF-α-induced increased paracellular flux of 4 kDa FITC-dextran in vitro. Moreover, both ectoines reduced expression of pro-inflammatory cytokines and oxidative stress during colitis. CONCLUSION: While both ectoine and homoectoine have protective effects on the epithelial barrier during inflammation, only homoectoine completely prevented the inflammatory claudin switch in tight junctions. Thus, homoectoine may serve as diet supplement in IBD patients to reach or extend remission.

Bioactive factors secreted from mesenchymal stromal cells protect the intestines from experimental colitis in a three-dimensional culture.

BACKGROUND AIMS: Although mesenchymal stromal cells (MSCs) have shown therapeutic potential in intestinal tissue repair, controversy concerning their short survival and poor biodistribution in recipient tissues still remains. Therefore, we investigated the paracrine role of MSC in three-dimensional culture of colon with experimental colitis. METHODS: Colitis was induced in mice by oral administration of dextran sulfate sodium (DSS) for 7 days. Inflammatory responses were assessed on the basis of clinical signs, morphological, and histopathological parameters. On days 2 and 5, colonic explants were removed, and a three-dimensional culture was performed. The structural integrity of the intestinal mucosa was tested by treating the cultures with MSC or conditioned medium (CM) for 24 h, and then the colons were analyzed for histology/immunohistochemistry and interleukin (IL)-6 production. RESULTS: Histological analysis demonstrated that both MSC and CM treatment reduced colon damage in organ culture. An increase in cell proliferation (Ki-67 staining) was observed after CM treatment. Additionally, MSC treatment was able to reduce CD3+ cells. The therapeutic effect of MSC and CM was mediated by the downregulation of IL-6. DISCUSSION: The intestinal in vitro model has shown to be potentially useful for studying cellular interactions in a three-dimensional cell arrangement. Moreover, our results provide strong evidence that both MSC and CM treatments can alleviate colonic damage in organ culture. Importantly, these results suggest that MSC-secreted factors are able to protect the colon from inflammation caused by DSS-induced colitis independent of cell transplantation.

Isolation and Characterization of Potentially Probiotic Bacterial Strains from Mice: Proof of Concept for Personalized Probiotics.

Modulation of the gut microbiota through the use of probiotics has been widely used to treat or prevent several intestinal diseases. However, inconsistent results have compromised the efficacy of this approach, especially in severe conditions such as inflammatory bowel disease (IBD). The purpose of our study was to develop a personalized probiotic strategy and assess its efficacy in a murine model of intestinal inflammation. Commensal bacterial strains were isolated from the feces of healthy mice and then administered back to the host as a personalized treatment in dextran sodium sulfate (DSS)-induced colitis. Colonic tissues were collected for histological analysis and to investigate inflammatory markers such as Il-1ß, Il-6, TGF-ß, and Il-10, and the enzyme myeloperoxidase as a neutrophil marker. The group that received the personalized probiotic showed reduced susceptibility to DSS-colitis as compared to a commercial probiotic. This protection was characterized by a lower disease activity index and reduced histopathological damage in the colon. Moreover, the personalized probiotic was more effective in modulating the host immune response, leading to decreased Il-1ß and Il-6 and increased TGF-ß and Il-10 expression. In conclusion, our study suggests that personalized probiotics may possess an advantage over commercial probiotics in treating dysbiotic-related conditions, possibly because they are derived directly from the host's own microbiota.

The Bisindole Alkaloid Caulerpin, from Seaweeds of the Genus Caulerpa, Attenuated Colon Damage in Murine Colitis Model.

Caulerpin (CLP), an alkaloid from algae of the genus Caulerpa, has shown anti-inflammatory activity. Therefore, this study aimed to analyze the effect of CLP in the murine model of peritonitis and ulcerative colitis. Firstly, the mice were submitted to peritonitis to evaluate which dose of CLP (40, 4, or 0.4 mg/kg) could decrease the inflammatory infiltration in the peritoneum. The most effective doses were 40 and 4 mg/kg. Then, C57BL/6 mice were submitted to colitis development with 3% dextran sulfate sodium (DSS) and treated with CLP at doses of 40 and 4 mg/kg. The disease development was analyzed through the disease activity index (DAI); furthermore, colonic tissue samples were submitted to histological analysis, NFκB determination, and in vitro culture for cytokines assay. Therefore, CLP at 4 mg/kg presented the best results, triggering improvement of DAI and attenuating the colon shortening and damage. This dose was able to reduce the TNF-α, IFN-γ, IL-6, IL-17, and NFκB p65 levels, and increased the levels of IL-10 in the colon tissue. Thus, CLP mice treatment at a dose of 4 mg/kg showed promising results in ameliorating the damage observed in the ulcerative colitis.

Salivary Gland Extract of Kissing Bug, Triatoma lecticularia, Reduces the Severity of Intestinal Inflammation through the Modulation of the Local IL-6/IL-10 Axis.

Triatomines are known for their role as vectors of the causative agent of Chagas disease. The occurrence of an arsenal of molecules in their saliva is able to suppress vertebrate immune responses. Thus, it is reasonable to assume that the presence of molecules with therapeutic potential in their saliva is able to constrain inflammation in immune-mediated diseases. Thus, mice were exposed to dextran sulfate sodium (DSS) in drinking water uninterruptedly during 6 consecutive days and treated with T. lecticularia salivary gland extract (SGE) (3, 10, or 30 µg) or vehicle (saline) (n = 6/group). At the highest dose (30 µg), an improvement in clinical outcome and macroscopic aspects of the intestine were observed. This observation was followed by amelioration in histopathological aspects in the colon especially when the doses of 10 and 30 µg were used. Regardless of the concentration used, treatment with T. lecticularia SGE significantly reduced the levels of the inflammatory cytokine IL-6 in the intestine. The production of the anti-inflammatory cytokine IL-10 was positively impacted by the concentrations of 3 and 30 µg. Our results suggest that the presence of molecules in the T. lecticularia SGE is able to attenuate clinical outcome and colon shortening and improve intestinal architecture besides reducing the production of IL-6 and inducing a local production of IL-10 in the intestine.

Acute infection with Strongyloides venezuelensis increases intestine production IL-10, reduces Th1/Th2/Th17 induction in colon and attenuates Dextran Sulfate Sodium-induced colitis in BALB/c mice.

Helminth infection can reduce the severity of inflammatory bowel disease. However, the modulatory mechanisms elicited by helminth infection are not yet fully understood and vary depending on the experimental model. Herein we evaluated the effect of acute infection of BALB/c mice with Strongyloides venezuelensis on the clinical course of ulcerative colitis induced by Dextran Sulfate Sodium (DSS) treatment of these animals. For the experiments, S. venezuelensis-infected BALB/c mice were treated orally with 4% DSS solution for seven days. As controls, we used untreated S. venezuelensis infected, DSS-treated uninfected, and untreated/uninfected BALB/c mice. During DSS treatment, mice from the different groups were compared with regards to the clinical signs related to the severity of colitis and intestinal inflammation. Mice acutely infected with S. venezulensis and treated with DSS had reduced clinical score, shortening of the colon, and tissue inflammation. Moreover, DSS-treated and infected mice showed reduced IL-4, INF-γ, and IL-17 levels and increase of IL-10 production in the colon and/or in the supernatant of mesenteric lymph nodes cell cultures that resulted in lower eosinophil peroxidase and myeloperoxidase activity in colon homogenates, when compared with DSS-treated uninfected mice. DSS-treated infected mice also preserved the intestine architecture and had normal differentiation of goblet cells and mucus production in the colon mucosa. In conclusion, the data indicate that the clinical improvement reported in DSS-treated infected mice was accompanied by the lower production of Th1/Th2/Th17 pro-inflammatory cytokines, stimulation of IL-10, and induction of mucosal repair mechanisms.

Propolis from Different Geographic Origins Decreases Intestinal Inflammation and Bacteroides spp. Populations in a Model of DSS-Induced Colitis.

SCOPE: Dietary supplementation with polyphenol-rich propolis can protect against experimentally induced colitis. We examined whether different polyphenol compositions of Chinese propolis (CP) and Brazilian propolis (BP) influence their ability to protect against dextran sulfate sodium (DSS)-induced colitis in rats. METHODS AND RESULTS: HPLC-DAD/Q-TOF-MS analysis confirmed that polyphenol compositions of CP and BP were dissimilar. Rats were given CP or BP by gavage (300 mg kg-1 body weight) throughout the study, starting 1 week prior to DSS treatment for 1 week followed by 3 d without DSS. CP and BP significantly reduced the colitis disease activity index relative to controls not receiving propolis, prevented significant DSS-induced colonic tissue damage, and increased resistance to DSS-induced colonic oxidative stress as shown by reduced malonaldehyde levels and increased T-AOC levels. CP and BP significantly reduced DSS-induced colonic apoptosis. Colonic inflammatory markers IL-1ß, IL-6, and MCP-1 were suppressed by CP and BP, whereas only BP-induced expression of TGF-ß. CP, not BP, increased the diversity and richness of gut microbiota populations. Both forms of propolis significantly reduced populations of Bacteroides spp. CONCLUSIONS: Despite the dissimilar polyphenol compositions of CP and BP, their ability to protect against DSS-induced colitis is similar. Nevertheless, some different physiological impacts were observed.