Chemically-induced Colitis Research Articles

In Vivo Assessment of Deep Vascular Patterns in Murine Colitis Using Optoacoustic Mesoscopic Imaging.

The analysis of vascular morphology and functionality enables the assessment of disease activity and therapeutic effects in various pathologies. Raster-scanning optoacoustic mesoscopy (RSOM) is an imaging modality that enables the visualization of superficial vascular networks in vivo. In murine models of colitis, deep vascular networks in the colon wall can be visualized by transrectal absorber guide raster-scanning optoacoustic mesoscopy (TAG-RSOM). In order to accelerate the implementation of this technology in translational studies of inflammatory bowel disease, an image-processing pipeline for TAG-RSOM data has been developed. Using optoacoustic data from a murine model of chemically-induced colitis, different image segmentation methods are compared for visualization and quantification of deep vascular patterns in terms of vascular network length and complexity, blood volume, and vessel diameter. The presented image-processing pipeline for TAG-RSOM enables label-free in vivo assessment of changes in the vascular network in murine colitis with broad applications for inflammatory bowel disease research.

The beneficial impact of ketogenic diets on chemically-induced colitis in mice depends on the diet's lipid composition

Previously, we showed that restrictive diets, including ketogenic diet (KD), have an anti-inflammatory impact on the healthy gastrointestinal tract of mice. Afterward, we found that energy-restricting diets mitigate inflammation in the dextran sodium sulfate (DSS) colitis mouse model. The current study aimed to verify the impact of KD on DSS colitis and assess if the diet's fat composition influences the outcomes of the intervention.Mice with mild chronic colitis were fed control chow, KD composed of long-chain triglycerides (KD LCT) or a KD containing a mix of LCT and medium-chain triglycerides (KD LCT/MCT).KDs did not reverse DSS-enhanced gut permeability and shortening of the colon. Both KDs had a similar impact on liver, cecum, and spleen weight, villi and colon length, the thickness of muscularis externa, and expression of ZO-1 and occludin. On the contrary, body weight, glutathione (GSH) and taurine-GSH levels, GSH-S transferase (GST), and myeloperoxidase (MPO) activity, as well as an abundance of several fecal bacteria, all were differentially affected by the two types of KDs. When compared to the DSS control diet, reduction in colon mucosa cytokines expression was stronger in KD LCT than in the KD LCT/MCT group.We conclude that the outcomes of the KD interventions in terms of potential therapeutical applications depend on lipid composition. KD LCT showed a strong positive impact on gut inflammation. A potential contribution of GSH to KD outcomes and a correlation between MPO activity and microbiota composition was identified.

Bromodomain-containing 4 is a positive regulator of the inflammatory cytokine response in the gut.

Bromodomain-containing protein 4 (BRD4), one of the components of the bromodomain and extraterminal domain (BET) family, is a transcriptional and epigenetic regulator of cellular proliferation and cytokine production. In this study, we assessed whether BRD4 regulates the cytokine response in inflammatory bowel diseases (IBD). BRD4 expression was analyzed in intestinal mucosal samples of patients with ulcerative colitis (UC), patients with Crohn's disease (CD), normal controls (CTRs), and mice with chemically-induced colitis by real-time PCR, Western blotting, and confocal microscopy. Cytokine production was evaluated in lamina propria mononuclear cells (LPMCs) of IBD patients and mucosal tissues of colitic mice treated with BRD4 inhibitors. Finally, we evaluated the effect of JQ1, an inhibitor of the BRD4 signaling pathway, on the course of murine colitis. BRD4 RNA and protein expression was up-regulated in the inflamed mucosa of patients with UC and patients with CD as compared to the uninvolved areas of the same patients and CTRs, and in the inflamed colon of colitic mice. Knockdown of BRD4 with a specific antisense oligonucleotide in IBD LPMCs led to reduced expression of TNF-α, IL-6, IFN-γ, and IL-17A. Administration of JQ1 to colitic mice inhibited the inflammatory cytokine response and attenuated the ongoing colitis. This is the first study showing the up-regulation of BRD4 in IBD and suggesting the role of such a protein in the positive control of the inflammatory cytokine response in the gut.

Ambient Particulate Matter Induces In Vitro Toxicity to Intestinal Epithelial Cells without Exacerbating Acute Colitis Induced by Dextran Sodium Sulfate or 2,4,6-Trinitrobenzenesulfonic Acid.

Inflammatory bowel disease (IBD) is an immunologically complex disorder involving genetic, microbial, and environmental risk factors. Its global burden has continued to rise since industrialization, with epidemiological studies suggesting that ambient particulate matter (PM) in air pollution could be a contributing factor. Prior animal studies have shown that oral PM10 exposure promotes intestinal inflammation in a genetic IBD model and that PM2.5 inhalation exposure can increase intestinal levels of pro-inflammatory cytokines. PM10 and PM2.5 include ultrafine particles (UFP), which have an aerodynamic diameter of <0.10 μm and biophysical and biochemical properties that promote toxicity. UFP inhalation, however, has not been previously studied in the context of murine models of IBD. Here, we demonstrated that ambient PM is toxic to cultured Caco-2 intestinal epithelial cells and examined whether UFP inhalation affected acute colitis induced by dextran sodium sulfate and 2,4,6-trinitrobenzenesulfonic acid. C57BL/6J mice were exposed to filtered air (FA) or various types of ambient PM reaerosolized in the ultrafine size range at ~300 μg/m3, 6 h/day, 3-5 days/week, starting 7-10 days before disease induction. No differences in weight change, clinical disease activity, or histology were observed between the PM and FA-exposed groups. In conclusion, UFP inhalation exposure did not exacerbate intestinal inflammation in acute, chemically-induced colitis models.

Hemodynamic Parameters in Spontaneously Hypertensive Rats with Obesity and Chemically Induced Colitis during Probiotic Therapy.

We studied the dynamics of the main hemodynamic parameters in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with visceral obesity and chemically induced colitis (CIC) against the background of probiotic therapy. Systolic BP, HR, and body temperature were recorded over 36 days using a wireless telemetry system. During 8 days (3 days before CIC induction and until the end of the experiment) the animals were intragastrically administered a probiotic based on Lactobacillus delbrueckii D5 strain. At baseline, systolic BP was significantly higher in the SHR group, while HR and body temperature did not differ in SHR and WKY rats. On day 8 after CIC induction, systolic BP, HR, and body temperature in SHR were significantly increased in comparison with the initial values. In the group of WKY rats, all indices at the end of the experiment remained at the initial levels. Probiotic therapy in SHR, in contrast to WKY rats, did not lead to normalization of body temperature and hemodynamic disorders resulting from CIC.

Arabinose confers protection against intestinal injury by improving integrity of intestinal mucosal barrier

There is a growing amount of research that highlights the significant involvement of metabolic imbalance and the inflammatory response in the advancement of colitis. Arabinose is a naturally occurring bioactive monosaccharide that plays a crucial role in the metabolic processes and synthesis of many compounds in living organisms. However, the more detailed molecular mechanism by which the administration of arabinose alleviates the progression of colitis and its associated carcinogenesis is still not fully understood. In the present study, arabinose is recognized as a significant and inherent protector of the intestinal mucosal barrier through its role in preserving the integrity of tight junctions within the intestines. Also, it is important to note that there is a positive correlation between the severity of inflammatory bowel disease (IBD) and colorectal cancer (CRC), as well as chemically-induced colitis in mice, and lower levels of arabinose in the bloodstream. In two mouse models of colitis, caused by dextran sodium sulfate (DSS) or by spontaneous colitis in IL-10-/- mice, damage to the intestinal mucosa was reduced by giving the mice arabinose. When arabinose is administrated to model with colitis, it sets off a chain of events that help keep the lysosomes together and stop cathepsin B from being released. During the progression of intestinal epithelial injury, this process blocks myosin light chain kinase (MLCK) from damaging tight junctions and causing mitochondrial dysfunction. In summary, the results of the study have provided evidence supporting the beneficial effects of arabinose in mitigating the progression of colitis. This is achieved through its ability to avoid dysregulation of the intestinal barrier. Consequently, arabinose may hold promise as a therapeutic supplementation for the management of colitis.

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice.

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

Inhibition of STAT-mediated cytokine responses to chemically-induced colitis prevents inflammation-associated neurobehavioral impairments

Depression can be associated with chronic systemic inflammation, and production of peripheral proinflammatory cytokines and upregulation of the kynurenine pathway have been implicated in pathogenesis of depression. However, the mechanistic bases for these comorbidities are not yet well understood. As tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO), which convert tryptophan to kynurenine, are rate-limiting enzymes of the kynurenine pathway, we screened TDO or IDO inhibitors for effects on the production of proinflammatory cytokines in a mouse macrophage cell line. The TDO inhibitor 680C91 attenuated LPS-induced pro-inflammatory cytokines including IL-1β and IL-6. Surprisingly, this effect was TDO-independent, as it occurred even in peritoneal macrophages from TDO knockout mice. Instead, the anti-inflammatory effects of 680C91 were mediated through the suppression of signal transducer and activator of transcription(STAT) signaling. Furthermore, 680C91 suppressed production of proinflammatory cytokines and STAT signaling in an animal model of inflammatory bowel disease. Specifically, 680C91 effectively attenuated acute phase colon cytokine responses in male mice subjected to dextran sulfate sodium (DSS)-induced colitis. Interestingly, this treatment also prevented the development of anxiodepressive-like neurobehaviors in DSS-treated mice during the recovery phase. The ability of 680C91 to prevent anxiodepressive-like behavior in response to chemically-induced colitis appeared to be due to rescue of attenuated dopamine responses in the nucleus accumbens. Thus, inhibition of STAT-mediated, but TDO-independent proinflammatory cytokines in macrophages can prevent inflammation-associated anxiety and depression. Identification of molecular mechanisms involved may facilitate the development of new treatments for gastrointestinal-neuropsychiatric comorbidity.

Weissella confusa F213 ameliorated inflammation and maintained intestinal mucosa integrity in chemically induced colitis rats

ObjectiveThis study was performed to investigate the potential effects of Weissella confusa F213 (WCF213) on chemically-induced colitis rats. Twelve male Wistar rats were divided into three groups: T1 (saline sterile), T2 (2.5% dextran sulfate sodium (DSS)- for 7 days), and T3 (WCF213 for 14 days, continued with 2.5% DSS for 7 days). The disease activity index (DAI) was monitored. After sacrificing the rats, the colon was collected for length measurement, local TNF-α level, HE staining for histology, and ZO-1 expression by using immunohistochemistry.ResultsWCF213 administration prevented weight loss and haematochezia, maintained average colon length and alleviated the clinical symptom of colitis, such as diarrhoea, albeit statistically non-significant (p < 0.05) compared with the T2 group. The histopathology of WCF213-treated colitis rats showed better architecture and less inflammatory cell infiltration into colon tissue. WCF213 significantly maintained the expression of ZO-1 in the mucosa (p < 0.001) and markedly reduced mucosal TNF-α concentration (p < 0.001) compared with the DSS group. Hence, these findings suggested that WCF213 attenuated clinical symptoms and inflammation and maintained mucosal integrity in DSS-induced colitis in vivo.

THE GUT MICROBIOME REGULATES EFFICACY OF SULFASALAZINE THERAPY FOR SPONDYLOARTHRITIS IN INFLAMMATORY BOWEL DISEASE

Abstract Joint inflammation, or spondyloarthritis (SpA), is the most common extra-intestinal manifestation of inflammatory bowel disease (IBD), but the specific role for therapies targeting SpA is not well defined. One of the earliest medications used for the treatment of IBD is sulfasalazine (SAS). SAS is a prodrug composed of two chemical moieties, the anti-inflammatory 5-aminosalicilate and the antibiotic sulfapyridine. The efficacy of SAS in peripheral arthritis is thought to depend on its “antibacterial” properties, however the impact of SAS on the IBD-SpA microbiome and how it may improve extra-intestinal symptoms is unknown. Therefore, our study aims to diagnostically evaluate the role for the fecal microbiome in clinical response to SAS therapy and identify microbial and immunologic therapeutic targets associated with clinical response. We have designed an observational study to longitudinally follow IBD patients with SpA who have a medical indication for SAS therapy. Clinical data and fecal samples from 22 patients were collected before initiation of SAS and at week 12 after initiation of SAS. Eleven IBD-SpA patients were concomitantly enrolled as controls and followed by 12 weeks. Metagenomic sequencing was used to define the effect of SAS on the IBD-SpA fecal microbiome and to evaluate its relationship with improvement in joint symptoms. Mouse models and in vitro assays were used to test the sufficiency of the SAS effect observed in patients. The fecal microbiome of SAS-responders was distinct from that observed in non-responders and 6 pre-treatment microbial markers (including the short chain fatty acid (SCFA) producer Faecalibacterium prausnitzii) predicted SAS-response (AUC = 0.9). Fecal metabolome of SAS responders had lower thymine and higher deoxyuridine compared to non-responders consistent with evidence of a folate trap in response to SAS treatment. SAS therapy in SPF mouse-model of chemically-induced colitis alleviated colitis in GPR 109a-dependent fashion consistent with a synergistic role for SCFA. In vitro assays revealed SAS direct regulation of F. prausnitzii metabolic function and butyrate synthesis. CONCLUSIONS: Collectively, these findings highlight the potential role for microbial diagnostics to improve SAS efficacy, and drug modulation of microbial markers to potentiate therapy for IBD patients with SpA.

Probiotic Therapy with Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis Results in Infarct Size Limitation in Rats with Obesity and Chemically Induced Colitis

In this study, we investigated the effect of three different probiotics, namely, a combination of Lactobacillus acidophilus (LA-5) and Bifidobacterium animalis subsp. lactis (BB-12), Saccharomyces boulardii, and Enterococcus faecium L3 on myocardial infarct size in rats with diet-induced obesity (DIO) and chemically-induced colitis (CIC). Potential associations between the effects of probiotics on myocardial ischemia-reperfusion injury and gut microbiome patterns as well as the serum levels of pro- and anti-inflammatory cytokines, lipopolysaccharide, and short chain fatty acids were also studied. Intragastric administration of lyophilized Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis at a dose of 1.2 × 108 CFU/mL for 15 days resulted in myocardial infarct size reduction in rats with DIO, CIC, and antibiotic-induced dysbiosis. This cardioprotective effect was associated with specific changes in cytokine concentrations, namely reduced levels of IL-1β, TNF-α, IL-2, and IL-8. At the same time, the use of Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis was accompanied by a significant reduction in lipopolysaccharide level, suggesting normalization of intestinal epithelial barrier permeability. However, the cardioprotective effect of Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis is not secondary to improved healing of the intestinal mucosa in CIC, as evidenced by the lack of difference in histopathological scores.

A steamed broccoli sprout diet preparation that reduces colitis via the gut microbiota

Sulforaphane is a bioactive metabolite with anti-inflammatory activity and is derived from the glucosinolate glucoraphanin, which is highly abundant in broccoli sprouts. However, due to its inherent instability its use as a therapeutic against inflammatory diseases has been limited. There are few studies to investigate a whole food approach to increase sulforaphane levels with therapeutic effect and reduce inflammation. In the current study, using a mouse model of inflammatory bowel disease, we investigated the ability of steamed broccoli sprouts to ameliorate colitis and the role of the gut microbiota in mediating any effects. We observed that despite inactivation of the plant myrosinase enzyme responsible for the generation of sulforaphane via steaming, measurable levels of sulforaphane were detectable in the colon tissue and feces of mice after ingestion of steamed broccoli sprouts. In addition, this preparation of broccoli sprouts was also capable of reducing chemically-induced colitis. This protective effect was dependent on the presence of an intact microbiota, highlighting an important role for the gut microbiota in the metabolism of cruciferous vegetables to generate bioactive metabolites and promote their anti-inflammatory effects.

A Specific Broccoli Sprout Preparation Reduces Chemically-Induced Colitis Via Gut Microbiota

ObjectivesSulforaphane is a bioactive metabolite with anti-inflammatory activity that is derived from glucosinolates, which are highly abundant in cruciferous vegetables including broccoli sprouts. There have been limited studies to investigate a whole foods approach to increase sulforaphane levels with therapeutic effect and reduce inflammation. In the current study, using a mouse model of inflammatory bowel disease, we aimed to investigate the ability of steamed broccoli sprouts to ameliorate colitis and the role of the microbiota in mediating any effects. MethodsC57BL/6J male mice were fed base diet or 5% steamed broccoli sprout diet for 2 weeks prior to induction of colitis with 2–3% DSS (5–7 days) and kept on their respective diets until sacrifice. Body weight and disease activity index scores were recorded daily, and histological assessment was performed on H&E sections of colon. Urine, feces, blood, and GI tract tissues and intestinal content were collected for LC-MS/MS quantification of sulforaphane and glucoraphanin. The 16S rRNA sequencing was performed to analyze gut microbiome. Germ-free mice were fed base diet or 5% steamed broccoli sprout diet for 2 weeks followed by treatment with 5 days of DSS to determine the role of gut microbiota in mediating the anti-inflammatory effects of the steamed broccoli sprout diet. ResultsWe observed that despite inactivation of the plant myrosinase enzyme responsible for the generation of sulforaphane via steaming, measurable levels of sulforaphane were detectable in the colon tissue and feces of mice after ingestion of steamed broccoli sprouts. In addition, this preparation of broccoli sprouts was also capable of reducing chemically-induced colitis. This protective effect was dependent on the presence of an intact gut microbiota, highlighting an important role for the microbiota in the metabolism of cruciferous vegetables to generate bioactive metabolites and promote their anti-inflammatory effects. ConclusionsAltogether, these results suggest that the incorporation of a steamed broccoli sprouts diet is a viable dietary intervention to complement current medical therapies for patients with inflammatory bowel disease. Funding SourcesThis work was supported by USDA-NIFA-AFRI Foundational Program [Grant No. 2018–67,017-27,520].

DEFINING THE ROLE FOR THE GUT MICROBIOME IN THE CLINICAL EFFICACY OF SULFASALAZINE THERAPY FOR IBD ASSOCIATED SPONDYLOARTHRITIS

Abstract Joint inflammation (spondyloarthritis, SpA), is the most common extra-intestinal manifestation of inflammatory bowel disease (IBD), but the specific role for therapies targeting SpA is not well defined. Sulfasalazine (SAS) is a prodrug composed of two chemical moieties, 5-aminosalicylate and the anti-folate antibiotic sulfapyridine, with efficacy in peripheral arthritis. Our study aims to evaluate the role for the gut microbiome in clinical response of SpA to SAS and to define microbial mechanisms targeted by SAS. We longitudinally follow IBD patients with SpA who have a medical indication for SAS therapy. Clinical data and fecal samples from 22 patients were collected before initiation of SAS and at week 12 after initiation of SAS. The fecal microbiome of SAS-responders was distinct from that observed in non-responders and 6 pre-treatment microbial markers (including the short chain fatty acid (SCFA) producer Faecalibacterium prausnitzii) predicted SAS-response (AUC=0.9). Fecal metabolome of SAS responders had lower thymine and higher deoxyuridine compared to non-responders consistent with evidence of a folate trap in response to SAS treatment. SAS therapy in SPF mouse-model of chemically-induced colitis alleviated colitis in GPR 109a- and 43-dependent fashion consistent with a synergistic role for SCFA. In vitro and in vivo models revealed SAS direct regulation of F. prausnitzii transcription and metabolic function and its impact on host immune response. Collectively, these findings highlight the potential role for microbial diagnostics to improve SAS efficacy, and drug modulation of microbial markers to potentiate therapy for IBD patients with SpA. Supported by New York Crohn's Foundation

Starch nanoparticles improve curcumin-induced production of anti-inflammatory cytokines in intestinal epithelial cells

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a long-term condition resulting from self-sustained intestinal inflammation. Curcumin (Cur), a powerful, naturally occurring antioxidant and anti-inflammatory polyphenol, has been investigated as a therapeutic for IBD, but its poor stability and low bioavailability limits its efficacy. We investigated the use of crosslinked starch nanocarrier (NPL) on the intracellular delivery and the anti-inflammatory efficiency of curcumin. Caco-2 epithelial cells were stimulated with TNFα for 24 h and the anti-inflammatory effects of NPL/Cur formulations were evaluated at the early stages of inflammation (4 h) or later, when fully established (24 h). NPL allowed the intracellular delivery of curcumin, which was enhanced in inflammatory cells, due to a modification of the endocytosis pathways. NPL/Cur decreased the secretion of pro-inflammatory cytokines IL-1β, IL-6 and IL-8 while increasing the anti-inflammatory cytokine IL-10. Finally, the inflammation-related opening of the tight junctions better allowed NPL/Cur to cross the epithelium by paracellular transport. This was confirmed by ex vivo analysis where NPL/Cur, administered to colonic explants from chemically-induced acute colitis mouse model, delivered curcumin deeper in the epithelium. To conclude, NPL/Cur formulation emphasizes the anti-inflammatory effects of curcumin and could constitute a therapeutic alternative in the management of IBD.

Effect of the qualitative composition of a high-fat diet in rats with systemic inflammatory response syndrome upon myocardial resistance to ischemic-reperfusion injury and cytokine levels

Overweight and obesity are among the main factors of cardiovascular risk, but the prospective studies on the dependence between high-fat diets and weight gain yielded contradictory results. Different types of fats exert varying metabolic effects, and this fact leads to a difference in the risk associated with increasing body weight. The effects of fat quality in the daily diet on immunological status and resistance of myocardium to ischemic-reperfusion damage should be studied experimentally in biomedical models. The purpose of this work was to assess the effect of the qualitative composition of a high-fat diet used for induction of primary visceral obesity (PVO) in rats with systemic inflammatory response syndrome (SIRS) upon myocardial resistance to ischemic-reperfusion injury, and levels of pro- and anti-inflammatory cytokines.The experiments were performed on adult male Wistar rats with PVO caused by 28-day consumption of any fat types: hydrogenated fats (HF), vegetable oils (VO), animal fats (AF) or milk fat (MF). The SIRS model included a combination of chemically induced colitis (CIC) and intragastric injection of a broad-spectrum antimicrobial agent (AMA) for three days. Five days later, immunological and biochemical studies were conducted, as well as composition of intestinal microbiota in faecal samples, morphological changes in the structure of the large intestine, hemodynamic parameters and myocardial resistance to ischemic-reperfusion injury were studied in the model of isolated heart perfusion, by Langendorff technique.There was a significant increase in the concentration of anti-inflammatory cytokines in animals with SIRS, i.e., TNFα, IL-1α, IL-2, IL-8, as well as a decrease in TGF-1β, an anti-inflammatory cytokine. SIRS was accompanied by severe dietary disorders and evacuatory function of the gastrointestinal tract. Minimal changes in the intestinal microbiota composition, as well as the most pronounced regeneration signs of intestinal epithelium was observed in rats in the group with MF injection. There was a trend for increasing size of infarction in all the groups as compared with control, directly correlating with increase in BDNF and IL-2 production. However, a significant increase in the infarction size was found only in the group receiving milkfat, thus suggesting a decrease in myocardial resistance to ischemic reperfusion injury (IRI).Thus, the presence of SIRS in the primary obesity model is characterized by controllable change of inflammation markers and depends on the quality of dietary fats. The degree of morphofunctional deterioration of isolated heart, including a decrease in resistance to ischemia-reperfusion injury, correlates with the concentration of BDNF and IL-2 during the studied observation terms.

Natural flavone tricin exerted anti-inflammatory activity in macrophage via NF-κB pathway and ameliorated acute colitis in mice

BackgroundUlcerative colitis is a subtype of inflammatory bowel disease, characterized by relapsing inflammation in the gastrointestinal tract with limited treatment options. Previous studies suggested that the natural compound tricin, a flavone isolated from rice bran, could suppress chemically-induced colitis in mice, while our recent study also demonstrated the anti-metastatic effect of tricin in colon tumor-bearing mice. Hypothesis/PurposeHere we further investigated the underlying mechanism of the inhibitory effects of tricin on lipopolysaccharides-activated macrophage RAW264.7 cells and explored the efficacy of tricin in acute colitis mouse model induced by 4.5% dextran sulfate sodium (DSS) for 7 days. MethodsTricin (75, 100, and 150 mg/kg) or the positive control drug sulfasalazine (200 mg/kg) were orally administered to mice for 7 days. Stool consistency scores, stool blood scores, and body weight were recorded daily. Disease activity index (DAI) was examined on day 7, and colon tissues were collected for biochemical analyses. The fecal microbiome of colitis mice after tricin treatment was characterized for the first time in this study using 16S rDNA amplicon sequencing. ResultsResults showed that tricin (50 µM) remarkably reduced nitric oxide production in lipopolysaccharides-activated RAW264.7 cells and the anti-inflammatory activity of tricin was shown to act through the NF-κB pathway. Besides, tricin treatment at 150 mg/kg significantly reversed colon length reduction, reduced myeloperoxidase activities and DAI scores, as well as restored the elevated myeloid-derived suppressive cells population in acute colitis mice. The influence from DSS on gut microbiota, such as the increased population of Proteobacteria phylum and Ruminococcaceae family, was shown to be relieved after tricin treatment. ConclusionOur present study firstly demonstrated that tricin ameliorated acute colitis by improving colonic inflammation and modulating gut microbiota profile, which supports the potential therapeutic use of tricin for colitis treatment.

Tranilast-loaded amorphous solid dispersion prepared with fine droplet drying process for improvement of oral absorption and anti-inflammatory effects on chemically-induced colitis

The aim of the present study was to evaluate the applicability of a tranilast (TL)-loaded amorphous solid dispersion prepared with a fine droplet drying (FDD) process for the treatment of inflammatory bowel diseases. The FDD process, a novel powderization technology using an inkjet head, was employed to produce an amorphous solid dispersion of tranilast (ASD/TL). The physicochemical properties of ASD/TL were evaluated in terms of the morphology, particle size, crystallinity, drug-polymer interaction, and dissolution behavior. The oral absorption behavior of TL and anti-inflammatory effect on a chemically-induced colitis model were evaluated after oral administration of TL samples. The particle size of ASD/TL was 4 μm, and the span factor, one of the parameters to present the uniformity of particle size distribution, was calculated to be 0.28. In each ASD/TL particle, TL was dispersed in an amorphous state in the carrier polymer, and ASD/TL showed improved dissolution behavior of TL, as evidenced by a 2-times higher dissolution than the equilibrium solubility of crystalline TL even under acidic conditions. Orally-dosed ASD/TL exhibited rapid and improved oral absorption with 16-fold higher bioavailability than crystalline TL. ASD/TL could significantly attenuate the inflammatory symptoms in the colon tissues of colitis model rats based on the results of histological analyses and measurement of biomarkers. ASD/TL might contribute to the development of effective treatment for inflammatory bowel diseases due to its enhanced biopharmaceutical properties.

Fish Sidestream-Derived Protein Hydrolysates Suppress DSS-Induced Colitis by Modulating Intestinal Inflammation in Mice.

Inflammatory bowel disease is characterized by extensive intestinal inflammation, and therapies against the disease target suppression of the inflammatory cascade. Nutrition has been closely linked to the development and suppression of inflammatory bowel disease, which to a large extent is attributed to the complex immunomodulatory properties of nutrients. Diets containing fish have been suggested to promote health and suppress inflammatory diseases. Even though most of the health-promoting properties of fish-derived nutrients are attributed to fish oil, the potential health-promoting properties of fish protein have not been investigated. Fish sidestreams contain large amounts of proteins, currently unexploited, with potential anti-inflammatory properties, and may possess additional benefits through bioactive peptides and free amino acids. In this project, we utilized fish protein hydrolysates, based on mackerel and salmon heads and backbones, as well as flounder skin collagen. Mice fed with a diet supplemented with different fish sidestream-derived protein hydrolysates (5% w/w) were exposed to the model of DSS-induced colitis. The results show that dietary supplements containing protein hydrolysates from salmon heads suppressed chemically-induced colitis development as determined by colon length and pro-inflammatory cytokine production. To evaluate colitis severity, we measured the expression of different pro-inflammatory cytokines and chemokines and found that the same supplement suppressed the pro-inflammatory cytokines IL-6 and TNFα and the chemokines Cxcl1 and Ccl3. We also assessed the levels of the anti-inflammatory cytokines IL-10 and Tgfb and found that selected protein hydrolysates induced their expression. Our findings demonstrate that protein hydrolysates derived from fish sidestreams possess anti-inflammatory properties in the model of DSS-induced colitis, providing a novel underexplored source of health-promoting dietary supplements.

IL-33 is produced by colon fibroblasts and differentially regulated in acute and chronic murine colitis

IL-33 is upregulated in ulcerative colitis and has a protective role in chemically-induced acute murine colitis. We aimed to determine whether IL-33 influences Il10−/− chronic colitis and its cellular source in health and during colitis. Il10−/−Il33−/− and Il10−/−Il33+/+ littermates developed colitis of similar severity. Colon Il33 was induced in WT and Il10−/− mice exposed to DSS, but not in unchallenged Il10−/− mice with colitis. Il33-citrine reporter mice showed that Il33-citrine colocalized with α-smooth muscle actin+ myofibroblasts and vimentin+ fibroblasts in WT mice. Citrine+CD74+CD90hi inflammatory fibroblasts were increased with DSS treatment. IL-1β induced Il33 expression in colon myofibroblasts, but colon Il33 expression did not differ between DSS-treated WT and Il1r1−/− mice. In conclusion, deficiency of IL-33 does not alter the severity of chronic colitis in Il10−/− mice. Induction of Il33 upon DSS exposure in WT and Il10−/− mice, but not in unchallenged Il10−/− mice, suggests epithelial injury induces colon IL-33. Fibroblasts are the primary colonic source of IL-33 and IL-33-expressing CD90hiCD74+ fibroblasts are increased during DSS-induced colitis. IL-1β induces Il33 in colon myofibroblasts in vitro, but signaling through the IL-1R1 is not necessary for induction of IL-33 in DSS-induced colitis.