Preclinical Models Of Inflammatory Bowel Disease Research Articles

ECCO Grant Investigating regenerative pathways in salivary glands to mitigate oral manifestations of inflammatory bowel diseases

Abstract Background and Aims Inflammatory bowel diseases (IBD) impact 4-16% of patients with extraintestinal manifestations in the upper gastrointestinal (GI) tract, including stomach and esophageal ulcers, dry mouth, taste alterations, halitosis, ulcers, and periodontitis. The underlying mechanisms remain unclear. This study hypothesizes that intestinal inflammation disrupts upper GI tract homeostasis by impairing salivary gland functions and aims to: Aim 1: Elucidate cellular and molecular mechanisms of intestinal inflammation on upper GI tract mucosa and salivary glands. Aim 2: Evaluate therapeutic potential of liver X receptor (LXR) activation in restoring salivary gland function in colitis-induced oral pathology. Methods I will use a novel mounting method for spatial proteogenomic analysis of upper GI tract mucosa to identify colitis-induced perturbations. Salivary glands will be studied separately, employing bulk and single-cell transcriptomic profiling to identify mechanisms driving colitis-induced atrophy, dysfunction, and candidate regenerative pathways. Additionally, salivary gland organoids will be used to study regeneration mechanisms in vitro, such as LXR activation, and the therapeutic potential of successful candidate pathways will be tested in vivo using pre-clinical models of colitis and salivary gland damage/repair (irradiation). Anticipated Impact This research will provide insights into mechanisms by which intestinal inflammation disrupts upper GI tract homeostasis through salivary gland impairment and assess the role of candidate pathways in salivary gland regeneration. In the short to medium term, findings may contribute to developing novel therapeutic strategies for managing colitis-induced oral pathology, benefiting the IBD community by improving patients' quality of life.

Resveratrol for inflammatory bowel disease in preclinical studies: a systematic review and meta-analysis.

Background: Inflammatory bowel disease (IBD) is a chronic condition that can be managed with treatment, but it is challenging to get IBD cured. Resveratrol, a non-flavonoid polyphenolic organic compound derived from various plants, has a potential effect on IBD. The current research was set out to investigate the therapeutic effects of resveratrol on animal models of IBD. Methods: A comprehensive search of PubMed, Embase, Web of Science, and Chinese databases was performed. The literature search process was completed independently by two people and reviewed by a third person. The risk of bias in the included literature was assessed using the Collaborative Approach to Meta Analysis and Review of Animal Data from Experimental Stroke (CAMARADES) 10-point quality checklist. The meta-analysis utilized Review Manager 5.4 software to evaluate the efficacy of resveratrol, with histopathological index as the primary outcome measure. Subgroup analysis was conducted based on this indicator. Additionally, meta-analyses were carried out on different outcomes reported in the literature, including final disease activity index, final body weight change, colon length, splenic index, and inflammatory factors. Results: After conducting a thorough literature search and selection process, a total of 28 studies were ultimately included in the analysis. It was found that over half of the selected studies had more than five items with low risk of bias in the bias risk assessment. Relevant datas from included literature indicated that the histopathological index of the resveratrol group was significantly lower than that of the control group (WMD = -2.58 [-3.29, -1.87]). Subgroup analysis revealed that higher doses of resveratrol (>80mg/kg) had a better efficacy (WMD = -3.47 [-4.97, -1.98]). Furthermore, The data summary and quantitative analysis results of SI and colon length also showed that resveratrol was effective in alleviating intestinal mucosal pathological injury of IBD. In terms of biochemical indicators, the summary analysis revealed that resveratrol affected interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), interferon-γ (IFN-γ), malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), and prostaglandin E2 (PGE2) significantly. These effects may be attributed to the mechanism of resveratrol in regulating immune response and inhibiting oxidative stress. Conclusion: This review suggests that resveratrol demonstrated a notable therapeutic impact in preclinical models of IBD, particularly at doses exceeding 80mg/kg. This efficacy is attributed to the protective mechanisms targeting the intestinal mucosa involved in the pathogenesis of IBD through various pathways. As a result, resveratrol holds promising prospects for potential clinical use in the future.

Acute Administration of Ojeok-san Ameliorates Pain-like Behaviors in Pre-Clinical Models of Inflammatory Bowel Diseases.

(1) Background: Gastrointestinal pain and fatigue are the most reported concerns of patients with inflammatory bowel disease (IBD). Commonly prescribed drugs focus on decreasing excessive inflammation. However, up to 20% of IBD patients in an "inactive" state experience abdominal pain. The medicinal herb Ojeok-san (OJS) has shown promise in the amelioration of visceral pain. However, no research on OJS has been conducted in preclinical models of IBD. The mechanism by which OJS promotes analgesia is still elusive, and it is unclear if OJS possesses addictive properties. (2) Aims: In this study, we examined the potential of OJS to promote analgesic effects and rewarding behavior. Additionally, we investigated if tumor necrosis factor alpha (TNFα) from macrophages is a primary culprit of IBD-induced nociception. (3) Methods: Multiple animal models of IBD were used to determine if OJS can reduce visceral nociception. TNFα-macrophage deficient mice were used to investigate the mechanism of action by which OJS reduces nociceptive behavior. Mechanical sensitivity and operant conditioning tests were used to determine the analgesic and rewarding effects of OJS. Body weight, colon length/weight, blood in stool, colonic inflammation, and complete blood count were assessed to determine disease progression. (4) Results: OJS reduced the evoked mechanical nociception in the dextran sulphate sodium model of colitis and IL-10 knockout (KO) mice and delayed aversion to colorectal distension in C57BL/6 mice. No rewarding behavior was observed in OJS-treated IL-10 KO and mdr1a KO mice. The analgesic effects of OJS are independent of macrophage TNFα levels and IBD progression. (5) Conclusions: OJS ameliorated elicited mechanical and visceral nociception without producing rewarding effects. The analgesic effects of OJS are not mediated by macrophage TNFα.

LRRK2 deficiency mitigates colitis progression by favoring resolution of inflammation and restoring homeostasis of gut microbiota

Leucine rich-repeat kinase 2 (LRRK2) has been considered a susceptibility gene for ulcerative colitis (UC), and its protein abundance was enhanced in the peripheral blood mononuclear cells (PBMCs) from UC cohorts as compared to healthy volunteers. In preclinical models of colitis, Lrrk2 deficiency ameliorated dextran sodium sulfate (DSS)-induced colitis progression, whereas the processes were aggravated by R1441C mutation. While intestinal macrophages (MФs) from Lrrk2 knock-out (Lrrk2−/−) mice exhibited a tendency to transit to alternatively activated MФs, R1441C MФs mutation facilitated the pro-inflammatory phenotype polarization, determined by RNA sequencing and qPCR. Moreover, we characterized their microbiota profiles and found that loss of Lrrk2 increased the bacterial richness and altered bacterial community structure, and this shift contributed to the alleviation of colitis development and progression. We proposed that Lrrk2 deficiency promotes M2 MФ transition and facilitates probiotics colonization, providing a protective role during colitis.

Neutrophils in Intestinal Inflammation: What We Know and What We Could Expect for the Near Future

Neutrophils are short-lived cells that play a crucial role in inflammation. As in other tissues, these polymorphonuclear phagocytes are involved in the intestinal inflammatory response, on the one hand, contributing to the activation and recruitment of other immune cells, but on the other hand, facilitating intestinal mucosa repair by releasing mediators that aid in the resolution of inflammation. Even though these responses are helpful in physiological conditions, excessive recruitment of activated neutrophils in the gut correlates with increased mucosal damage and severe symptoms in patients with inflammatory bowel disease (IBD) and pre-clinical models of colitis. Thus, there is growing interest in controlling their biology to generate novel therapeutic approaches capable of reducing exacerbated intestinal inflammation. However, the beneficial and harmful effects of neutrophils on intestinal inflammation are still controversial. With this review, we summarise and discuss the most updated literature showing how neutrophils (and neutrophil extracellular traps) contribute to developing and resolving intestinal inflammation and their putative use as therapeutic targets.

Interleukin 15 in murine models of colitis.

Inflammatory bowel diseases (IBDs) are characterized by abnormal, non-antigen specific chronic inflammation of unknown etiology. Genome-wide association studies show that many IBD genetic susceptibility loci map to immune function genes and compelling evidence indicate that environmental factors play a critical role in IBD pathogenesis. Clinical and experimental evidence implicate the pro-inflammatory cytokine IL-15 in the pathogenesis of IBD. IL-15 and IL-15α expression is increased in the inflamed mucosa of IBD patients. IL-15 contributes to the maintenance of different cell subsets in the intestinal mucosa. However, very few studies have addressed the role of IL-15 in pre-clinical models of colitis. In this study, we use three well-characterized models of experimental colitis to determine the contribution of IL-15 to pathological intestinal inflammation.

Small intestine neuromuscular dysfunction in a mouse model of dextran sulfate sodium-induced ileitis: Involvement of dopaminergic neurotransmission

AimsAnomalies in dopaminergic machinery have been shown in inflammatory bowel disease (IBD) patients and preclinical models of IBD. Thus, we aimed to evaluate the impact of dextran sodium sulfate (DSS)-induced ileitis on enteric dopaminergic pathways. Materials and methodsMale C57/Bl6 mice (10 ± 2 weeks old) received 2% DSS in drinking water for 5 days and were then switched to regular drinking water for 3 days. To measure ileitis severity inflammatory cytokines (IL-1β, TNFα, IL-6) levels were assessed. Changes in ileal muscle tension were isometrically recorded following: 1) cumulative addition of dopamine on basal tone (0.1–1000 μM); ii) 4-Hz electric field stimulation (EFS) in the presence of 30 μM dopamine with/without 10 μM SCH-23390 (dopamine D1 receptor (D1R) antagonist) or 10 μM sulpiride (D2R antagonist). Immunofluorescence distribution of the neuronal HuC/D protein, glial S100β marker, D1R, and dopamine transporter (DAT) were determined in longitudinal-muscle-myenteric plexus whole-mounts (LMMPs) by confocal microscopy. D1R and D2R mRNA transcripts were evaluated by qRT-PCR. Key findingsDSS caused an inflammatory process in the small intestine associated to dysmotility and altered barrier permeability, as suggested by decreased fecal output and enhanced stool water content. DSS treatment caused a significant increase of DAT and D1R myenteric immunoreactivity as well as of D1R and D2R mRNA levels, accompanied by a significant reduction of dopamine-mediated relaxation, involving primarily D1-like receptors. SignificanceMouse ileitis affects enteric dopaminergic neurotransmission mainly involving D1R-mediated responses. These findings provide novel information on the participation of dopaminergic pathways in IBD-mediated neuromuscular dysfunction.

P011 New insights into the pathogenic potential and signalling network of NKG2D+ CD4+ T-cells in Crohn’s Disease

Abstract Background A subset of mucosal CD4+ T-cells expressing the NK cell receptor NKG2D (encoded by the KLRK1 gene) are enriched in patients with Crohn’s Disease (CD). In pre-clinical models of colitis, NKG2D expression was confined to a subset of colonic CD4+ T-cells that hyper-expressed interferon gamma. However, the functional role of these cells in mediating intestinal inflammation is unknown. Little is known about the transcriptional regulation of this population or the key signalling networks that they engage. Methods Pre-clinical models of CD, adoptive transfer experiments and in vitro culture systems were used to investigate the phenotype and pathogenicity of NKG2D using Klrk1-/- and WT mice. Signalling networks and interactions between NKG2D, key transcription factors and relevant cytokines were investigated by probing published single-cell RNA seq data (Martin et al. Cell 2019). Pathway members of potential interactions were collected from the literature, and the OmniPath database and we applied a heat propagation model. Results NKG2D-expressing T-cells were potently pathogenic when adoptively transferred to Rag1- mice, mediating more severe disease than Klrk1-/- CD4+ T-cells. Notably, Klrk-/- T-cells were still able to induce colitis, indicating that NKG2D-independent pathogenic pathways also exist. Chromatin immunoprecipitation demonstrated that T-bet bound at the transcriptional start site of the Klrk1 locus in WT Th1 cells, but not Tbx21-/- Th1 T-cells. There were significantly fewer NKG2D expressing CD4+ T-cells from Tbx21-/- mice, and forced expression of T-bet in Tbx21-/-Ifng-/- double knockout CD4+ T-cells induced Klrk1 mRNA expression, consistent with T-bet being a transcriptional activator of the Klrk1 gene. The NKG2D model network reached FOS, NFKB and JUN transcription factors depending on the presence of the NKG2D. The model distinguished two comparable pathway activation - one with active PRKCA in T-cells including CD8+ T-cells and one with less active PRKCA mostly in macrophages. Comparing the inflamed and uninflamed conditions, highly activated T-cells, and a population of Th17+ TRM cells had an active KLRK pathway only in inflamed Crohn disease. Conclusion NKG2D expressing colonic CD4+ T-cells are potent cytokine producing cells and are more colitigenic than their NKG2D-negative counterparts. Network-based heat propagation showed that specific populations of colonic memory T cells are active only in the inflamed condition, meanwhile, the model identified two types of cells that had active KLRK1 pathway: one which was PRKCA dependent activity and one which had non-PRKCA dependent activity. We also identify T-bet as an important transcriptional regulator of NKG2D expression.

Therapeutic Interleukin-6 Trans-signaling Inhibition by Olamkicept (sgp130Fc) in Patients With Active Inflammatory Bowel Disease

A large unmet therapeutic need exists in inflammatory bowel disease (IBD). Inhibition of interleukin (IL)-6 appears to be effective, but the therapeutic benefit of a complete IL6/IL6 receptor (IL6R) blockade is limited by profound immunosuppression. Evidence has emerged that chronic proinflammatory activity of IL6 is mainly mediated by trans-signaling via a complex of IL6 bound to soluble IL6R engaging the gp130 co-receptor without the need for membrane-bound IL6R. We have developed a decoy protein, sgp130Fc, that exclusively blocks IL6 proinflammatory trans-signaling and has shown efficacy in preclinical models of IBD, without signs of immunosuppression. We present a 12-week, open-label, prospective phase 2a trial (FUTURE) in 16 patients with active IBD treated with the trans-signaling inhibitor olamkicept (sgp130Fc) to assess the molecular mechanisms, safety, and effectiveness of IL6 trans-signaling blockade invivo. We performed in-depth molecular profiling at various timepoints before and after therapy induction to identify the mechanism of action of olamkicept. Olamkicept was well tolerated and induced clinical response in 44% and clinical remission in 19% of patients. Clinical effectiveness coincided with target inhibition (reduction of phosphorylated STAT3) and marked transcriptional changes in the inflamed mucosa. An olamkicept-specific transcriptional signature, distinguishable from remission signatures of anti-tumor necrosis factor (infliximab) or anti-integrin (vedolizumab) therapies was identified. Our data suggest that blockade of IL6 trans-signaling holds great promise for the therapy of IBD and should undergo full clinical development as a new immunoregulatory therapy for IBD. (EudraCT no., Nu 2016-000205-36).

P157 FBXO3-FBXL2 AXIS MODULATORS AS A NOVEL CLASS OF ORAL SMALL MOLECULE COMPOUNDS FOR THE TREATMENT OF CROHN’S DISEASE

Abstract Background Ubiquitination is a common post-translational modification, tagging proteins for degradation. The ubiquitin proteasome system is activated in Crohn’s Disease (CD), and modulation of its components might be a novel strategy for therapeutic intervention to control inflammation. The conjugation of ubiquitin to a target protein is orchestrated by a series of enzymatic reactions, the last step being catalyzed by a selective ubiquitin E3 ligase. Among ubiquitin E3 ligases, Fbxl2 serves as a sentinel gatekeeper to limit inflammation by targeting and enhancing the degradation of tumor necrosis factor receptor associated factors (TRAF) proteins, which link cell surface signals (through NFkB signaling) to cytokine secretion. In addition, Fbxl2 controls the ubiquitination of the inflammasome, NOD-like receptor protein 3 (NLRP3), which mediates the release of interleukin (IL)1β and IL18 (Fig.1). Fbxl2 protein itself is ubiquitinated and degraded by another protein, called Fbxo3. Inhibition of Fbxo3 results in increased Fbxl2 levels and decreased TRAF and NLRP3. Individuals with a natural occurring polymorphism within Fbxo3V221Ihave decreased lipopolysaccharide(LPS)-induced cytokine (TNFα, IL1β & IL6) production, Fbxo3 and TRAF levels and increased Fbxl2, providing human genetic target validation for Fbxo3-Fbxl2 axis modulation in inflammatory conditions. BC1261 is a first-in-class, selective, orally available Fbxo3 inhibitor in clinical development for the treatment of CD. Methods and Results In vitro data demonstrated that BC1261 binds to Fbxo3, prevents Fbxo3/Fbxl2 association and produces a concentration-dependent inhibition of LPS-induced release of TNFα and IL1β from human peripheral blood mononuclear cells. In an acute DSS-mouse model, administration of BC-1261 via drinking water ad libitum (30 μg/ml) or by daily intraperitoneal (IP) injection (150 μg) for 5 days resulted in the attenuation of the shortening of colonic length, tissue damage (Fig2.A), and TNFα and IL6 tissue levels (Fig.2B). In a repeated DSS-mouse model, BC-1261 (10 mg/kg bid) given orally for 19 days was comparable to the positive control (anti-p40) in the DAI composite (Fig2.C), stool consistency (Fig2.D), and histopathology score in the proximal colon (Fig2.E). BC-1261 also lead to clinically relevant reductions on endoscopy score (Fig2.F). Conclusion BC1261, a Fbxo3 inhibitor, was efficacious in both acute and chronic preclinical models of colitis. Taken together, these results suggest the potential utility of selective Fbxo3-Fbxl2 modulation in the treatment of CD.

Exploratory clinical characterization of experimentally-induced ulcerative colitis nonhuman primates

A limitation of currently used preclinical models of colitis is that disease and treatment assessment methods differ from clinically used methods. Thus, a modified Mayo score and an endoscopic index (EI) were developed for use in cynomolgus macaques with 0.25% dextran sulfate sodium (DSS)-induced ulcerative colitis. Macaques were treated with water with DSS for two weeks followed by water without DSS for two weeks. Disease activity was classified according to a modified Mayo score: stool consistency, rectal bleeding, colonoscopy examination and global assessment. Findings on colonoscopy were further graded according the Rachmilewitz EI. To demonstrate the sensitivity of the modified Mayo score and EI to therapeutic intervention, macaques were treated with the anti-inflammatory steroid prednisolone followed eight weeks later by the integrin antibody vedolizumab. Before DSS treatment, normal stool consistency and no rectal bleeding were observed. Colonoscopy demonstrated no mucosal abnormalities. Following the first DSS treatment, Mayo score and EI indicated signs of mild colitis. Following subsequent DSS treatments, mild to moderate colitis emerged with each DSS treatment and reduced signs of colitis were observed 2 weeks after DSS treatment termination. Prednisolone treatment during DSS treatment suppressed the emergence of colitis. Vedolizumab reduced signs of colitis during DSS treatment and further reduced signs of colitis that persisted after termination of DSS treatment. The current study demonstrated the potential of utilizing clinical outcome measures to assess experimentally-induced colitis in the macaque. Furthermore, signs of colitis, as assessed with the current methods, were reduced following therapeutic treatment. The current findings suggest that clinically relevant outcome measures in the macaque model of ulcerative colitis could be used to test novel treatments.

Bacteroides thetaiotaomicron Ameliorates Colon Inflammation in Preclinical Models of Crohn's Disease.

BackgroundAlterations in the gut microbiota are strongly associated with the development of inflammatory bowel disease (IBD), particularly with Crohn’s disease, which is characterized by reduced abundance of commensal anaerobic bacteria including members of the Bacteroides genus. Our aim was to investigate the protective effects of Bacteroides thetaiotaomicron, an abundant member of this genus, in different rodent models of IBD.MethodsWe assessed the effect of B. thetaiotaomicron administration on primary readouts of colitis (weight loss, histopathology, and immune parameters) in dextran sodium sulphate (DSS) and interleukin-10 knockout (IL10KO) models of IBD. Efficacy of a freeze-dried bacterial formulation and a purified recombinant protein of B. thetaiotaomicron was also investigated.Results B. thetaiotaomicron showed protective effects in both DSS and IL10KO rodent models, as demonstrated by significant amelioration of weight loss, colon shortening, histopathological damage and immune activation. This efficacy was not exclusive to actively growing bacterial preparations but was retained by freeze-dried cells of B. thetaiotaomicron. A pirin-like protein (PLP) of B. thetaiotaomicron, identified by microarray analysis during coculture of the bacterial strain with Caco-2 cells, reduced pro-inflammatory NF-κB signalling in these intestinal epithelial cells. Recombinant PLP partially recapitulated the effect of the whole strain in a rat DSS model.Conclusions B. thetaiotaomicron displays strong efficacy in preclinical models of IBD and protects against weight loss, histopathological changes in the colon and inflammatory markers. These data indicate that the live strain or its products may be a novel alternative to current treatment options for Crohn’s disease.

P022 Severe disease activity in UC is associated with mucosal hypoxia measured endoscopically

Tissue hypoxia has been shown to be a key microenvironmental regulator of mucosal barrier function and inflammation in pre-clinical models of colitis. However, the role of mucosal hypoxia in the pathogenesis of UC has yet to be extensively studied in IBD patients. Visible light spectroscopy can be utilised to measure the haemoglobin (Hb) oxygen saturations (%) colonic mucosa during endoscopy. Carbonic anhydrase 9 (CA-9) is a hypoxia-inducible protein and endogenous marker of hypoxia. The aim of this study was to compare mucosal oxygen saturations in normal and inflamed colonic mucosa in UC patients and assess relationship with disease activity. Patients undergoing colonoscopy were prospectively recruited in a single academic centre, with >3800 IBD patients. Endoscopies were performed using CO2 insufflation. Measurements of colonic mucosal Hb saturations were performed segmentally and from zones of transition from inflamed to normal mucosa, using an endoscopic probe (applied to intact mucosa) and tissue oximeter (T-Stat System, Spectros).Endoscopic severity was graded using the endoscopic Mayo score. Mucosal biopsies were obtained to grade histologic activity and for protein analysis. 38 patients were included in this study; n = 7 controls, n = 31 UC; male=25 (65.7%). The median age of UC patients was 39 years (IQR 34.6- 55.9). n = 5 had Mayo 0, n = 9 Mayo 1, n = 11 Mayo 2 and n = 6 Mayo 3 activity. At the time of the procedure, five patients were on biologic therapy, five immunomodulators and six on steroids. The median rectal saturation in the control group was 76.2% (IQR 73–80),compared with 77% (IQR 73.8–80.6) in the UC cohort (Mayo 0–3 inclusive) (p = 1.00). There was no significant difference across any colonic segment between these two cohorts. The median rectal mucosal O2 saturation in Mayo 0 was 77.6% (77.4–81.2),Mayo 1: 80.6% (77–83.8), Mayo 2: 75.4% (73.5–79.2) and Mayo 3:73.3% (68.7–74.8) (p = 0.02). Mucosal Hb Saturations (%) by disease severity. CA9 protein expression was significantly higher in biopsies with Mayo 2–3 activity compared with Mayo 0-1 disease. CA-9 protein expression in rectal biopsies. Mucosal O2 saturation is significantly decreased in severely active UC and oxygen signalling pathways are activated suggesting that mucosal hypoxia is an important determinant of disease severity in UC. These observations suggest the potential for oxygen signalling pathways as novel therapeutic targets.

Epicutaneous Tolerance Induction to a Bystander Antigen Abrogates Colitis and Ileitis in Mice.

Although inflammatory bowel disease (IBD) is a failure in maintaining tolerance to the intestinal microbiota, few studies have investigated the use of immunologic tolerance as a treatment approach for IBD. We hypothesized that induction of immune tolerance at a distal site could suppress intestinal inflammation through a process of bystander regulation. Epicutaneous tolerance was induced by topical application of ovalbumin (OVA) using a Viaskin patch for 48 hours. In some experiments, a single feed of ovalbumin was used to drive epicutaneous tolerance-induced regulatory T cells (Tregs) to the intestine. The mechanism of tolerance induction was tested using neutralizing antibodies against TGF-β, IL-10, and Treg depletion using Foxp3-DTR mice. The capacity of skin-draining Tregs, or epicutaneous tolerance, to prevent or treat experimental IBD was tested using T-cell transfer colitis, dextran sodium sulfate (DSS) colitis, and ileitis in SAMP-YITFc mice. Weight loss, colonic inflammatory cytokines and histology were assessed. Epicutaneous exposure to ovalbumin induced systemic immune tolerance by a TGF-β-dependent, but IL-10 and iFoxp3 Treg-independent mechanism. Skin draining Tregs suppressed the development of colitis. Epicutaneous tolerance to a model antigen prevented intestinal inflammation in the dextran sodium sulfate and SAMP-YITFc models and importantly could halt disease in mice already experiencing weight loss in the T-cell transfer model of colitis. This was accompanied by a significant accumulation of LAP and Foxp3 Tregs in the colon. This is the first demonstration that epicutaneous tolerance to a model antigen can lead to bystander suppression of inflammation and prevention of disease progression in preclinical models of IBD.

The Bisphosphonate Pamidronate is an Intestinal Antiinflammatory Agent in Rat and Mouse Experimental Colitis.

Statins have antiinflammatory effects at the cardiovascular level because of inhibition of prenylation, which also probably underlies their therapeutic effects in preclinical models of inflammatory bowel disease. Another inhibitor of prenylation, namely alendronate, reduces colitis in rodents. In this study, we aim to explore the therapeutic potential of second-generation, nitrogen-containing bisphosphonates in 3 preclinical models of colitis. The trinitrobenzenesulfonic acid and dextran sulfate sodium models of rat colitis and the adoptive lymphocyte transfer model of colitis in mice were used. Pamidronate, alendronate, and ibandronate were tested. Treatments were administered in equimolar doses through the oral or intraperitoneal route. The effect of pamidronate on prenylation and cytokine release was assessed in vivo and in vitro. Pretreatment with pamidronate, but not with ibandronate or alendronate, improves chemically induced trinitrobenzenesulfonic acid and dextran sulfate sodium colitis in rats. Moreover, this beneficial effect is extended to lymphocyte transfer colitis. Pamidronate has no effect on intestinal epithelial cells in vitro in terms of cytokine/chemokine release, but enhances IFN-γ, IL-6, and IL-10 production by T cells in coculture. Pamidronate also exerts a direct immunomodulatory effect on T cells, favoring Th1 differentiation and impairing Th17 polarization. Pamidronate presents antiinflammatory and immunomodulatory properties in 3 different models of experimental colitis in rodents. This effect requires oral administration and may involve T cells in the gut mucosa, although the exact mechanism is unclear.

Molecular Imaging in Preclinical Models of IBD with Nuclear Imaging Techniques: State-of-the-Art and Perspectives.

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is characterized by chronic unregulated inflammation of the intestinal mucosa of the gastrointestinal tract. To date, this pathology has no cure. Colonoscopy and biopsies are the current gold standard diagnostic tools. However, being a chronic disease, IBD requires continuous follow-up to check for disease progress, treatment response, and remission. Unfortunately, these 2 diagnostic procedures are invasive and generally unable to show the cellular and molecular changes that take place in vivo. In this context, it is clear that there is a strong need for optimized noninvasive imaging techniques able to overcome the aforementioned limitations. This review aims to bring to light the scientific advancements that have been achieved so far in nuclear medicine in relation to tracking of immune cells involved in the preclinical models of IBD. In particular, this review will explore the advantages and limitations of the radiopharmaceuticals that aim to track whole cells like neutrophils, those that involve the radiolabeling of immune cell substrates or available human IBD medical therapies, and those that aim to track cell signaling molecules (e.g., cytokines and cell adhesion molecules). After a detailed critical summary of the state-of-the art, the challenges and perspectives of molecular imaging applied to IBD studies will be analyzed. Special attention will be paid to the translational potential of the described techniques and on the potential impact of these innovative approaches on the drug discovery pipelines and their contribution to the evolution of personalized medicine.

Tu1880 TOP1210 NSKI Demonstrates Superior Activity and Improved Safety Profile Potential Compared to Corticosteroid and Immunomodulators in Preclinical Models of Colitis

Tu1880 TOP1210 NSKI Demonstrates Superior Activity and Improved Safety Profile Potential Compared to Corticosteroid and Immunomodulators in Preclinical Models of Colitis

P064. TOP1210 narrow spectrum kinase inhibitor demonstrates superior activity and improved safety profile potential compared with corticosteroid and immunomodulators in preclinical models of colitis

P064. TOP1210 narrow spectrum kinase inhibitor demonstrates superior activity and improved safety profile potential compared with corticosteroid and immunomodulators in preclinical models of colitis

Faecalibacterium prausnitzii prevents physiological damages in a chronic low-grade inflammation murine model.

BackgroundThe human gut houses one of the most complex and abundant ecosystems composed of up to 1013-1014 microorganisms. The importance of this intestinal microbiota is highlighted when a disruption of the intestinal ecosystem equilibrium appears (a phenomenon called dysbiosis) leading to an illness status, such as inflammatory bowel diseases (IBD). Indeed, the reduction of the commensal bacterium Faecalibacterium prausnitzii (one of the most prevalent intestinal bacterial species in healthy adults) has been correlated with several diseases, including IBD, and most importantly, it has been shown that this bacterium has anti-inflammatory and protective effects in pre-clinical models of colitis. Some dysbiosis disorders are characterized by functional and physiological alterations. Here, we report the beneficial effects of F. prausnitzii in the physiological changes induced by a chronic low-grade inflammation in a murine model. Chronic low-grade inflammation and gut dysfunction were induced in mice by two episodes of dinitro-benzene sulfonic acid (DNBS) instillations. Markers of inflammation, gut permeability, colonic serotonin and cytokine levels were studied. The effects of F. prausnitzii strain A2-165 and its culture supernatant (SN) were then investigated.ResultsNo significant differences were observed in classical inflammation markers confirming that inflammation was subclinical. However, gut permeability, colonic serotonin levels and the colonic levels of the cytokines IL-6, INF-γ, IL-4 and IL-22 were higher in DNBS-treated than in untreated mice. Importantly, mice treated with either F. prausnitzii or its SN exhibited significant decreases in intestinal permeability, tissue cytokines and serotonin levels.ConclusionsOur results show that F. prausnitzii and its SN had beneficial effects on intestinal epithelial barrier impairment in a chronic low-grade inflammation model. These observations confirm the potential of this bacterium as a novel probiotic treatment in the management of gut dysfunction and low-grade inflammation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0400-1) contains supplementary material, which is available to authorized users.

S1pping fire: Sphingosine-1-phosphate signaling as an emerging target in inflammatory bowel disease and colitis-associated cancer

Inflammatory bowel disease (IBD) is a complex disease that involves unpredictable and destructive inflammation in the gastrointestinal tract resulting in gastrointestinal symptoms, infection, and tissue destruction, and which can be associated with an increased risk of colon cancer. The underlying cause of IBD involves disruption of the innate and adaptive immune mechanisms that maintain homeostasis between the gut mucosa and its environment. Elucidating how the homeostatic mechanisms controlling gut mucosal immunity and inflammation are disrupted in IBD represents the first steps to identifying novel therapeutic targets. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that is enriched in the blood and lymph, and functions in innate and adaptive immunity. S1P signaling regulates inflammation via its impact on the trafficking, differentiation, and effector functions of bone marrow-derived immune cells. S1P also activates nuclear factor kappa B and signal transducer and activator of transcription 3 inflammatory pathways. S1P is generated by the ubiquitously expressed lipid kinase, sphingosine kinase (SphK)1 and its tissue-restricted homolog, SphK2. S1P is irreversibly degraded by S1P lyase, which is highly expressed in enterocytes. Recent studies targeting S1P metabolism and signaling have shown promise in preclinical models of IBD and have shed light on the mechanisms by which S1P signaling impacts IBD. The evidence suggests that targeting S1P signaling and metabolism may represent a novel strategy in treating IBD and it may reduce colon cancer risk by interrupting the progression from inflammation to carcinogenesis.