Tobacco Alkaloid Assessment in a DSS-Induced Colitis Mouse Model with a Fully Humanized Immune System.

Inflammatory bowel disease (IBD) refers to chronic intestinal immune-mediated diseases including two main disease manifestations: ulcerative colitis (UC) and Crohn's disease (CD). Epidemiological, clinical, and preclinical evidence has highlighted the potential anti-inflammatory properties of naturally occurring alkaloids. In the present study, we investigated the potential anti-inflammatory activities of the tobacco alkaloids nicotine and anatabine in a dextran sulfate sodium (DSS)-induced UC mouse model with a fully humanized immune system. Our results show that nicotine significantly reduced all acute colitis symptoms and improved colitis-specific endpoints, including histopathologically assessed colon inflammation, tissue damage, and mononuclear cell infiltration. The tobacco alkaloid anatabine showed similar effectiveness trends, although they were generally weaker or not significant. Gene expression analysis in the context of biological network models of IBD further pinpointed a possible mechanism by which nicotine attenuated DSS-induced colitis in humanized mice. The current study enables further investigation of possible molecular mechanisms by which tobacco alkaloids attenuate UC symptoms.

Immune checkpoint Inhibitor-Induced diarrhea and Colitis: Incidence and Management. A systematic review and Meta-analysis.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved cancer outcomes. However, immune-related adverse effects are common. The aim was to investigate the incidence of diarrhea and colitis of ICIs alone and in combination with chemotherapy or tyrosine kinase inhibitors (TKIs), histopathological findings, and management. METHODS: Two separate studies, including meta-analyses, were performed. Key inclusion criteria were for Study I) phase I-IV trials, and data on diarrhea and/or colitis; for Study II) studies describing histopathologic and endoscopic findings and/or biologic treatment for ICI-induced colitis. RESULTS: The incidence of anti-PD-1/PD-L1 antibody-induced diarrhea and colitis was 10% and 2%, respectively, with no clinically relevant differences between the compounds. The CTLA-4 inhibitor, ipilimumab, induced diarrhea and colitis in 33% and 7% of patients, respectively, whereas the incidence of diarrhea and colitis following ipilimumab combined with nivolumab was 21%-37% and 4%-8%, depending on regimen. The incidence of all-grade diarrhea following ICIs combined with chemotherapy or TKIs was high (17%-56%), whereas only 0.5% of patients developed severe (≥grade 3) colitis. The main patterns of histopathologic presentation after PD-1/CTLA-4 inhibitor mono- or combination therapy were acute and chronic active colitis and microscopic colitis-like. Infliximab and vedolizumab were equally effective against ICI-induced colitis. CONCLUSION: Expanding treatment options include combinations of ICIs and chemotherapy/TKI with a high incidence of diarrhea and a low incidence of colitis; thus, a potential risk of overtreatment with corticosteroids exists. We suggest a more tailored approach, particularly for the management of low-grade diarrhea. Prospective clinical trials are needed to refine management.

Immunotherapy-induced Colitis: A Comprehensive Review of Epidemiology, Clinical Presentation, Diagnostic Workup, and Management Plan.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of a variety of malignancies including advanced melanoma, non-small cell lung cancer, renal cell carcinoma, head and neck cancers among others. Since their introduction, there has been significant improvement in survival and prognosis in patients with advanced malignancies. Unfortunately, improved outcomes have come at a price of significant immune-related adverse events, with those of the gastrointestinal tract being the most common. Gastrointestinal immune-related adverse events frequently present as diarrhea and colitis, the severity of which can range from mild diarrhea to fulminant colitis with intestinal perforation. Currently, management of ICI-induced colitis is primarily guided by retrospective studies and expert opinion. A significant number of ICI-induced colitis responds to high-dose corticosteroids; however, some patients require further therapy with biologics. There is limited information on the factors which may predispose patients to ICI-induced colitis. Future research elucidating these risk factors along with development of a scoring system could allow for risk-stratification of patients before initiation of ICI therapy. Such a system may help clinicians and patients keep a high index of suspicion regarding ICI-induced colitis and could hopefully reduce the incidence of severe cases. Similarly, future studies should investigate protective factors against ICI-induced colitis, which could potentially allow more patients to safely benefit from ICI therapy.

Recommendations for standardizing biopsy acquisition and histological assessment of immune checkpoint inhibitor-associated colitis.

Immune checkpoint inhibitor-associated colitis (ICIC) affects approximately 15% of cancer patients treated with immunotherapy. Although histological evaluation is potentially valuable for both the diagnosis of ICIC and evaluation of disease activity, use in clinical practice is heterogeneous. We aimed to develop expert recommendations to standardize histological assessment of disease activity in patients with ICIC. Using the modified Research and Development/University of California Los Angeles (RAND/UCLA) appropriateness methodology, an international panel of 11 pathologists rated the appropriateness of 99 statements on a 9-point Likert scale during two rounds of anonymous voting. Results were discussed between rounds using moderated videoconferences. There are currently no disease-specific instruments for assessing histological features of ICIC. The panel considered that colonoscopy with at least three biopsies per segment from a total of at least five segments, including both endoscopically normal and inflamed areas, was appropriate for tissue acquisition. They agreed that biopsies should be oriented such that the long axis of the colonic crypts is visualized and should be stained with hematoxylin and eosin. Histological items that the panel voted were appropriate to evaluate in ICIC included the degree of structural/architectural change, chronic inflammatory infiltrate, lamina propria and intraepithelial neutrophils, crypt abscesses and destruction, erosions/ulcerations, apoptosis, surface intraepithelial lymphocytosis, and subepithelial collagen thickness. The appropriateness of routine immunohistochemistry was uncertain. These expert recommendations will help standardize assessment of histological activity in patients with ICIC. The panel also identified the development and validation of an ICIC-specific histological index as a research priority.

Microbial hydrogen economy alleviates colitis by reprogramming colonocyte metabolism and reinforcing intestinal barrier.

With the rapid development and high therapeutic efficiency and biosafety of gas-involving theranostics, hydrogen medicine has been particularly outstanding because hydrogen gas (H2), a microbial-derived gas, has potent anti-oxidative, anti-apoptotic, and anti-inflammatory activities in many disease models. Studies have suggested that H2-enriched saline/water alleviates colitis in murine models; however, the underlying mechanism remains poorly understood. Despite evidence demonstrating the importance of the microbial hydrogen economy, which reflects the balance between H2-producing (hydrogenogenic) and H2-utilizing (hydrogenotrophic) microbes in maintaining colonic mucosal ecosystems, minimal efforts have been exerted to manipulate relevant H2-microbe interactions for colonic health. Consistent with previous studies, we found that administration of hydrogen-rich saline (HS) ameliorated dextran sulfate sodium-induced acute colitis in a mouse model. Furthermore, we demonstrated that HS administration can increase the abundance of intestinal-specific short-chain fatty acid (SCFA)-producing bacteria and SCFA production, thereby activating the intracellular butyrate sensor peroxisome proliferator-activated receptor γ signaling and decreasing the epithelial expression of Nos2, consequently promoting the recovery of the colonic anaerobic environment. Our results also indicated that HS administration ameliorated disrupted intestinal barrier functions by modulating specific mucosa-associated mucolytic bacteria, leading to substantial inhibition of opportunistic pathogenic Escherichia coli expansion as well as a significant increase in the expression of interepithelial tight junction proteins and a decrease in intestinal barrier permeability in mice with colitis. Exogenous H2 reprograms colonocyte metabolism by regulating the H2-gut microbiota-SCFAs axis and strengthens the intestinal barrier by modulating specific mucosa-associated mucolytic bacteria, wherein improved microbial hydrogen economy alleviates colitis.

Magnetic resonance colonography assessment of acute trinitrobenzene sulfonic acid colitis in pre-pubertal rats.

Pre-pubertal murine models of acute colitis are lacking. Magnetic resonance colonography (MRC) is a promising minimally invasive tool to assess colitis. We aimed to: 1/ Adapt a model of acute experimental colitis to pre-pubertal rats and determine whether MRC characteristics correlate with histological inflammation. 2/ Test this model by administering a diet supplemented in transforming growth factor ß2 to reverse inflammation. Twenty-four rats were randomized at weaning to one of 3 groups: Trinitrobenzene Sulfonic Acid (TNBS) group (n = 8) fed a standard diet, that received an intra-rectal 60 mg/kg dose of TNBS-ethanol; Control group (n = 8) fed standard diet, that received a dose of intra-rectal PBS; TNBS+MODULEN group (n = 8) that received a dose of TNBS and were exclusively fed MODULEN-IBD® after induction of colitis. One week after induction of colitis, rats were assessed by MRC, colon histopathology and inflammation markers (Interleukin 1ß, Tumor necrosis factor α, Nitric Oxide Synthase 2 and Cyclooxygenase 2). TNBS induced typical features of acute colitis on histopathology and MRC (increased colon wall thickness, increased colon intensity on T2-weighted images, target sign, ulcers). Treatment with MODULEN-IBD® did not reduce signs of colitis on MRC. Inflammatory marker expression did not differ among study groups.

An ultralow dose of the NADPH oxidase inhibitor diphenyleneiodonium (DPI) is an economical and effective therapeutic agent for the treatment of colitis-associated colorectal cancer.

Long-term inflammatory stimulation is considered one of the most important causes of colorectal cancer. Diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, can inhibit a variety of inflammatory responses. However, the systemic toxicity of DPI limits its clinical application. Whether DPI can inhibit colitis-associated colorectal cancer (CAC) at ultralow concentrations remains unknown. Methods: CAC was induced by azoxymethane (AOM) injection followed by treatment with dextran sulfate sodium (DSS), and DPI was intraperitoneally injected (i.p.) in the first cycle for 21 days. Colon tissue was collected and analyzed by western blotting. Immune cell infiltration and macrophage polarization were examined by immunohistochemistry, immunofluorescence, or real-time polymerase-chain reaction (PCR). Reactive oxygen species (ROS) production was measured by flow cytometry. Results: Ultralow dose DPI significantly ameliorated the DSS-induced colitis and attenuated the colon tumorigenesis in the mouse model of AOM/ DSS-induced CAC. Mechanistically, an ultralow dose of DPI inhibited the production of pro-inflammatory cytokines, (tumor necrosis factor (TNF)-α and interleukin (IL)-6), reduced the macrophage infiltration and classical polarization, and induced the ROS generation. These effects were found to be related to the inhibition of the phosphorylation of signal transducer and activator of transcription 3 (STAT3), mitogen-activated protein kinase (MAPK), and nuclear factor kappa B (NF -κB). Conclusion: The present study revealed that an ultralow dose of DPI, with no significant systemic toxicity involved, may be an effective way to prevent the occurrence and development of CAC.

Immune checkpoint inhibitor-related colitis assessment and prognosis: can IBD scoring point the way?

BACKGROUND: Immune checkpoint inhibitors (ICI) improve survival but cause immune-related adverse events (irAE). We sought to determine if CTCAE classification, IBD biomarkers/endoscopic/histological scores correlate with irAE colitis outcomes. METHODS: A dual-centre retrospective study was performed on patients receiving ICI for melanoma, NSCLC or urothelial cancer from 2012 to 2018. Demographics, clinical data, endoscopies (reanalysed using Mayo/Ulcerative Colitis Endoscopic Index of Severity (UCEIS) scores), histology (scored with Nancy Index) and treatment outcomes were analysed. RESULTS: In all, 1074 patients were analysed. Twelve percent (134) developed irAE colitis. Median patient age was 66, 59% were male. CTCAE diarrhoea grade does not correlate with steroid/ infliximab use. G3/4 colitis patients are more likely to need infliximab (p < 0.0001) but colitis grade does not correlate with steroid duration. CRP, albumin and haemoglobin do not correlate with severity. The UCEIS (p = 0.008) and Mayo (p = 0.016) scores correlate with severity/infliximab requirement. Patients with higher Nancy indices (3/4) are more likely to require infliximab (p = 0.03). CONCLUSIONS: CTCAE assessment does not accurately reflect colitis severity and our data do not support its use in isolation, as this may negatively impact timely management. Our data support utilising endoscopic scoring for patients with >grade 1 CTCAE disease, and demonstrate the potential prognostic utility of objective histologic scoring.

Immune-checkpoint inhibitors induced diarrhea and colitis: a review of incidence, pathogenesis and management.

PURPOSE OF REVIEW: Diarrhea and colitis are among the most commonly encountered immune-mediated adverse events among patients receiving antiprogrammed cell death protein/ligand-1 (PD-1/L1) as well as anticytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies. With growing indications and widespread use of immune checkpoint inhibitors, it is imperative to summarize the current body of evidence concerning the incidence, pathogenesis, risk factors, diagnostic challenges, and treatment options currently available for the management of immune-mediated diarrhea and colitis. Additionally, with emerging evidence analyzing the resumption of immune checkpoint inhibitors, it is pivotal to summarize our current understanding and future challenges. RECENT FINDINGS: Immune-mediated diarrhea and colitis can potentially be a viable surrogate marker for improved survival as it is validated further in large-scale studies. Early endoscopic evaluation can aid in the identification of patients at risk of developing steroid refractory immune-mediated colitis, and hence can be chosen to receive early add-on therapy with infliximab, vedolizumab or fecal microbiota transplantation, an emerging treatment option for immune-mediated diarrhea and colitis. Resuming immune checkpoint inhibitors carries a manageable risk of recurrent diarrhea and colitis, with most cases being mild and effectively managed with immunosuppressive therapy. SUMMARY: As our understanding of immune-mediated diarrhea and colitis grows, it is likely that this clinicopathologic entity will represent more than just an adverse event. With a growing number of treatment options, the management algorithms for immune-mediated diarrhea/colitis are likely to evolve in the future.

Variation in the Assessment of Immune-Related Adverse Event Occurrence, Grade, and Timing in Patients Receiving Immune Checkpoint Inhibitors.

Importance: Toxic effects of conventional chemotherapy and molecularly targeted cancer therapies are generally well defined and occur at predictable points. By contrast, owing to their heterogeneous manifestations, unpredictable timing, and clinical overlap with other conditions, immune-related adverse events (irAE) may be more difficult to diagnose and characterize. Objective: To determine concordance of algorithm-driven medical record review by medical oncologists for the characterization of 8 irAE in patients treated with immune checkpoint inhibitors. Design, Setting, and Participants: Cross-sectional study of patients treated with immune checkpoint inhibitors at a National Cancer Institute-designated comprehensive cancer center from November 30, 2015, to March 7, 2018. A sample size of 52 patients provided 80% power to distinguish substantial agreement (κ = 0.85) from poor agreement (κ = 0.5) based on the Cohen κ. Main Outcomes and Measures: Interrater agreement of 2 observers in the occurrence and grade of irAE. Results: Of 52 patients (32 [61.5%] male; mean [SD] age, 69 [9] years) analyzed, 42 (80.8%) had non-small cell lung cancer and all received anti-programmed cell death 1 or anti-programmed cell death ligand 1 antibodies, with 3 patients (5.8%) receiving combinations with anti-cytotoxic T-lymphocyte antigen 4 antibodies. A median (interquartile range) of 82 (47-180) documents were reviewed per case. There was limited or poor interrater agreement on irAE occurrence (Cohen κ, 0.37-0.64), with the exception of hypothyroidism (κ = 0.8). Weighted κ similarly showed limited or poor agreement for irAE grade (κ = 0.31-0.75). Differences in assessed time of onset ranged from 5 to 188 days. As a control for data availability and access, observers had a high degree of agreement for the exact start date (98%) and end date (96%) of immunotherapy administration, suggesting that information interpretation rather than identification largely accounted for assessment differences. In multivariable analysis, therapy duration (adjusted odds ratio, 4.80; 95% CI, 1.34-17.17; P = .02) and Charlson Comorbidity Index (adjusted odds ratio, 4.09; 95% CI, 1.10-15.18; P = .03) were significantly associated with discordant irAE assessment. Conclusions and Relevance: These findings underscore critical challenges in assessing the occurrence, type, timing, and severity of irAE. Apart from hypothyroidism (a condition that has a discrete diagnostic laboratory test and few other likely etiologies during immunotherapy treatment), interobserver agreement was poor. Given the importance of accurate and timely assessment of toxic effects for clinical trials and real-world disease management, efforts to improve irAE diagnosis and characterization are needed.

Changes in colonic contractility in response to inflammatory bowel disease: Long-term assessment in a model of TNBS-induced inflammation in rats.

AIMS: Inflammatory bowel disease is a chronic relapsing inflammation that affects the gastrointestinal tract, causing changes in colonic motility. The evolution of these changes is not completely understood and possibly related to symptoms that appear in different degrees of the intestinal inflammation. Therefore, our aim is evaluate during 14 days of assessment aspects of colonic contractility using 2,4,6-trinitrobenzenesulfonic acid (TNBS) model of inflammation in rats and associate the inflammatory process with colonic motility. METHODS: Contractility and inflammatory parameters were assessed in the same animal in six different moments: before intestinal inflammation induction, 2, 5, 8, 11, and 14 days after induction. The mechanical activity was determined by alternating current biosusceptometry (ACB) and subdivided into rhythmic propagating ripples (RPR) and rhythmic propulsive motor complexes (RPMC). We assessed inflammation by determining myeloperoxidase activity in feces. RESULTS: Transient and permanent changes were observed in colonic motility as a function of the inflammatory process evaluated through myeloperoxidase activity. We identified two contraction profiles: RPR and RPMC. The microscopic analysis demonstrated a depth of damage caused by an injury that was associated with changes in motility. CONCLUSIONS: We implemented a robust and adequate (specific) signal processing to quantify two measured colonic frequency patterns. Thus, we performed a detailed temporal analysis of the consequences of TNBS-induced inflammation on colonic motility in rats. Our approach enables further long-term assessments in the same animal with different mechanisms and duration of injury, remission, treatments and their motor consequences.

Pathological assessment of gastrointestinal biopsies from patients with idelalisib-associated diarrhea and colitis.

AIM: Idelalisib (IDELA) treatment is associated with diarrhea/colitis (incidence of ∼15% grade ≥3). We performed a retrospective analysis of gastrointestinal biopsies from 29 patients treated with IDELA across nine clinical trials. METHODS: A central core laboratory performed histopathologic review, immunohistochemistry, and droplet digital PCR viral studies. These results were correlated with tissue immune profiling data and morphologic features per modified Geboes score. RESULTS: Out of 29 eligible patients with abdominal pain or diarrhea, 24 (82.8%) had reported adverse event terms of diarrhea and/or colitis. Infectious pathogens were detected in 9/29 samples. Most biopsies presented with mixed/inflammatory infiltrates and contained increased numbers of FOXP3+ cells versus normal controls. CONCLUSION: This study revealed evidence of T-cell dysregulation and a substantial infectious component in association with IDELA-related diarrhea/colitis.

The cost of ipilimumab toxicity: a single-centre analysis.

There are no published data on the costs associated with investigating and managing toxicity from ipilimumab treatment in patients with metastatic melanoma. Patients treated with ipilimumab at The Royal Marsden Hospital between 1 September 2010 and 1 April 2013 were identified. Data on demographics, investigations and survival outcomes were collected. Patients with grade 3 or higher immune-related adverse events were identified, and costs of investigating and managing toxicities in them were calculated on the basis of standard National Health Service tariffs. Out of the 110 patients, 29 experienced grade 3/4 immune-related adverse events. The total cost of investigating and managing these patients was £140,680, or a median cost of £2860 per patient. Patients experiencing grade 3/4 toxicities had 1-, 2- and 3-year survival rates of 79, 59 and 46%, compared with 24, 17 and 15% in the group that did not experience significant toxicity (P<0.0005). The most common treatment-related toxicity identified was colitis. Two patients died from complications associated with ipilimumab colitis. The cost of ipilimumab toxicity is marginal in comparison with the total treatment cost. Patients treated with ipilimumab who develop significant toxicity have a higher than expected 1-, 2- and 3-year survival.

The association of antibiotic treatment regimen and hospital mortality in patients hospitalized with Legionella pneumonia.

BACKGROUND: Guidelines recommend azithromycin or a quinolone antibiotic for treatment of Legionella pneumonia. No clinical study has compared these strategies. METHODS: We performed a retrospective cohort analysis of adults hospitalized in the United States with a diagnosis of Legionella pneumonia in the Premier Perspectives database (1 July 2008-30 June 2013). Our primary outcome was hospital mortality; we additionally evaluated hospital length of stay, development of Clostridium difficile colitis, and total hospital cost. We used propensity-based matching to compare patients treated with azithromycin vs a quinolone. All analyses were repeated on a subgroup of more severely ill patients, defined as requiring intensive care unit admission or mechanical ventilation or having a predicted probability of hospital mortality in the top quartile for all patients. RESULTS: Legionella pneumonia was diagnosed in 3152 adults across 437 hospitals. Quinolones alone were used in 28.8%, azithromycin alone was used in 34.0%, and 1.8% received both. Crude hospital mortality was similar: 6.6% (95% confidence interval [CI], 5.0%-8.2%) for quinolones vs 6.4% (95% CI, 5.0%-7.9%) for azithromycin (P = .87); after propensity matching (n = 813 in each group), mortality remained similar (6.3% [95% CI, 4.6%-7.9%] vs 6.5% [95% CI, 4.8%-8.2%], P = .84 for the whole cohort, and 14.9% [95% CI, 10.0%-19.8%] vs 18.3% [95% CI, 13.0%-23.6%], P = .36 for the more severely ill). There was no difference in hospital length of stay, development of C. difficile, or total hospital cost. CONCLUSIONS: Use of azithromycin alone or a quinolone alone for treatment of Legionella pneumonia was associated with similar hospital mortality. Few patients receive combination therapy.

Magnetic resonance colonography for fibrosis assessment in rats with chronic colitis.

BACKGROUND: Magnetic resonance colonography (MRC) has been developed to assess inflammatory bowel diseases. We aimed to assess the feasibility of MRC in rats with TNBS-induced chronic colitis and to confront imaging results with fibrosis and stenosing features of the model. MATERIALS AND METHODS: Chronic colitis was induced in 12 rats by weekly intra-rectal injection of increasing doses of TNBS for 6 weeks, while 8 control rats received the vehicle. At week 7, MRC was performed. Fibrosis scores were assessed and fibrosis mediators measured. RESULTS: Chronic colitis was associated with significant body weight loss (p<0.0001) and higher colon weight/length compared to controls (p = 0.0004). Fibrosis mediators and histological scores were significantly higher in rats with TNBS than in controls: α-SMA expression (0.9 versus 0.61, p = 0.0311) and fibrosis score (p = 0.0308). Colon wall thickness was higher in rats with TNBS than in controls: maximal thickness (2.38 versus 0.74 mm, p<0.0001) and minimal thickness (1.33 versus 0.48 mm, p<0.0001). Wall signal intensity on T2w images was higher in rats with TNBS than in controls (9040 versus 6192, p = 0.0101) and correlated with fibrosis score (r = 0.5214; p = 0.04). Luminal narrowing was higher in rats with TNBS (50.08 versus 10.33%, p<0.0001) and correlated with α-SMA expression (r = 0.5618; p = 0.01). Stenosis was observed in 7/9 rats with TNBS and in no controls (p = 0.0053). CONCLUSIONS: MRC is feasible and easily distinguishes rats with colitis from controls. MRC signs correlated with fibrosis parameters. MRC evaluation may be part of a new anti-fibrosis drug assessment in experimental models of chronic colitis.

Small-intestinal manifestations of dextran sulfate sodium consumption in rats and assessment of the effects of Lactobacillus fermentum BR11.

The dextran sulfate sodium (DSS) colitis model has been utilized to screen for novel therapeutics for ulcerative colitis. Evidence suggests the small intestine may also be affected by DSS. We characterized the effects of DSS on the small intestine and assessed the potential for Lactobacillus fermentum BR11 to modify or normalize DSS-induced changes. Rats were allocated to three groups, Water + Vehicle, DSS + Vehicle, and DSS + L. fermentum BR11. BR11 was administered twice daily for 14 days. DSS (2%) was provided from days 7 to 14. Small-intestinal tissue was analyzed for sucrase activity, histology, and crypt cell proliferation. Increased ileum crypt depth and cell proliferation was observed in DSS-treated rats compared to controls (P < 0.05). BR11 normalized these parameters. While DSS predominantly induces colonic damage, minor morphological alterations were also detected in the distal small intestine. L. fermentum BR11 normalized these features.

The application and relevance of ex vivo culture systems for assessment of IBD treatment in murine models of colitis.

The aim of this study was to investigate the relevance of mouse ex vivo cultures as a first screening model for new therapeutic agents of Inflammatory Bowel Disease (IBD). Two murine models (dextran sodium sulphate (DSS)-induced colitis and Galphai2-deficient mice) and two anti-inflammatory agents (methyl-prednisolone and the proteasome inhibitor MG132) were evaluated. The in vivo effects of methyl-prednisolone were assessed in both models. Ex vivo colonic tissue from both mouse models were cultured in the presence or absence of the drugs and TaqMan Low-Density arrays were used to assess the regulation of inflammatory genes before and after drug treatment. Colitis induced a similar inflammatory gene profile in both mouse models in in vivo studies and in ex vivo cultures. The differences encountered reflected the different phases of colitis in the models, e.g. innate cytokine/chemokine profile in the DSS model and T cell related markers in Galphai2-deficient mice. After steroid treatment, a similar pattern of genes was suppressed in the two mouse models. We confirmed the suppression of inflammatory gene expression for IL-1beta, IL-6 and iNOS in ex vivo and in vivo colons from both mouse models by quantitative RT-PCR. Importantly, the inflammatory responses in the murine ex vivo culture system reflected the in vivo response in the inflamed colonic tissue as assessed by changes in inflammatory gene expression, suggesting that the murine culture system can be used for validation of future IBD therapies.

Immunohistochemical assessment of mucosal cytokine profile in acetic acid experimental colitis.

UNLABELLED: Experimental colitis induced by acetic acid has been used extensively as a model for intestinal inflammatory disease. Colonic tissue lesions of intestinal inflammatory disease patients seem to be related to the increased local production of pro-inflammatory cytokines (IL-1, IL-6, TNF-alpha, and IFN-gamma). PURPOSE: To assess the cytokine expression pattern identified through immunohistochemistry in colonic mucosa after experimental colitis induced by acetic acid and establish the relationship between this pattern and the presence of macroscopic lesions. MATERIALS AND METHODS: Adult male Wistar rats (n = 39) were divided at random into 4 groups: NC45 and NC24 (control without colitis; sacrificed at 45 minutes and 24 hours, respectively); and WC45 and WC24 (with experimental colitis induced by acetic acid; sacrificed at 45 minutes and 24 hours, respectively). Macroscopic and microscopic alterations in colonic tissue were evaluated, and cytokine expression was assessed through immunohistochemistry. RESULTS: After 24 hours, IL-1 expression was greater in the groups with colitis when compared to the groups without colitis. IL-4 expression was higher in the WC45 group. There was an increase in both INF-gamma and IL-6 related to the presence of necrosis of the colonic mucosa in the groups with colitis for both periods evaluated. CONCLUSION: The immunohistochemical technique was efficient for the analysis of various cytokine expressions in the colonic tissue. There was an increase in the IL-1 pro-inflammatory cytokines as well as in IL-6 and IFN-gamma associated with the presence of colonic necrosis. Experimental colitis induced by acetic acid is a useful model for the development of studies assessing the role of cytokines in the inflammation of mucosa as well as anti-cytokine therapies.

Immunohistochemical assessment of mucosal cytokine profile in acetic acid experimental colitis

O modelo de colite experimental induzida por ácido acético (CEAA) vem sendo extensamente utilizado em estudos sobre doenças inflamatórias intestinais (DII). Lesões no tecido colônico em portadores de DII parecem estar relacionados à produção local aumentada de citocinas pró-inflamatórias (IL-1, IL-6, TNF-a e IFN-g). OBJETIVO: Avaliar o padrão de expressão de citocinas identificadas por imunohistoquímica em tecido colônico após CEAA e relacioná-lo à presença de lesões macroscópicas. MATERIAL E MÉTODOS: Ratos machos Wistar adultos (n=39) foram submetidos ou não à CEAA e sacrificados para retirada do tecido colônico em dois períodos distintos, perfazendo 4 grupos aleatórios: SC45 e SC24 (sem colite; sacrifício 45 minutos e 24 horas, respectivamente); CC45 e CC24 (com colite; sacrifício 45 minutos e 24 horas, respectivamente). Avaliaram-se alterações macro e microscópicas do cólon e sua expressão de citocinas foi avaliada por imunohistoquímica. RESULTADOS: Após 24 horas, a expressão de IL-1 foi maior no grupo com colite, em relação ao sem colite. IL-4 foi mais expressa no grupo CC45. Houve aumento de INF-g e IL-6, relacionados à presença de necrose da mucosa colônica, nos grupos com colite, em ambos os períodos avaliados. CONCLUSÃO: A técnica de imunohistoquímica foi eficiente para a análise da expressão de citocinas na mucosa colônica. Houve aumento da expressão das citocinas pró-inflamatórias IL-1 e de IL-6 e IFN-g associado à presença de necrose colônica. A CEAA é um bom modelo para o desenvolvimento de estudos destinados a avaliar o papel das citocinas na inflamação da mucosa e terapias anti-citocinas.

Identification and evaluation of a possible signal of exacerbation of colitis during rofecoxib treatment, using Prescription-Event Monitoring data.

BACKGROUND: Identifying previously unrecognized adverse drug reactions (signals) is an important part of post-marketing surveillance. Automated signal generation now forms part of routine surveillance of spontaneous adverse drug reactions reported to the UK Yellow Card system. The Drug Safety Research Unit (DRSU) provides an additional post-marketing drug surveillance scheme in the UK, using the non-interventional observational cohort technique of Prescription-Event Monitoring (PEM), and systematically collects data on patients who were prescribed selected newly licensed drugs in primary care clinical practice. The introduction of a new computer system in January 2000 enabled the development of an automated signal generation system to compliment the process of identification of possible safety signals in drug data collected using PEM. AIMS: To use incidence rate ratios (IRRs) as a form of signal generation in the DSRU database, with particular interest in rofecoxib, plus further evaluation of any signal(s) of interest by requesting additional information from the general practioner (GP) of each relevant case. METHODS: Crude IRRs were calculated for each event term of interest by comparing the incidence rate for each lower term event reported in rofecoxib users with the comparable incidence rate for the whole PEM database (77 drugs of various therapeutic classes) from the total person-exposure time up to 180 days after starting the drug. To investigate a possible class effect, IRRs were also calculated using a second comparator cohort including only those PEM study drugs within the same therapeutic class (non-steroidal anti-inflammatory drugs, NSAIDs) and used for similar indications. Cases arising out of potential signals were followed up for additional information. RESULTS: A potential signal of 'colitis' was identified when rofecoxib was compared with the rest of the database, IRR 5.8 (95% CI 2.7,11.3; z statistic 5.6), and when the comparator group was changed to include only the other four NSAIDs, IRR 4.3 (95% CI 1.4,14.5; z statistic 2.8). Other possible signals, compared with the rest of the database, included events deemed to be related to the underlying condition, labelled adverse events and events describing effectiveness of treatment. Further evaluation of this signal revealed that there were 11 reports of colitis (two reports for one patient) that occurred while taking rofecoxib and within 180 days of exposure. A causality assessment for these 10 patients did not confirm an association with newly developing colitis, but showed that the events were 'possible' exacerbations of pre-existing colitis during treatment with rofecoxib. CONCLUSIONS: The use of IRRs for signal generation using PEM data is worthwhile and enables time to be taken into account. Previously unrecognized adverse events require further evaluation to confirm that a possible safety signal exists. In this study, the number of patients reported to have colitis was small but compared with other drugs on the database, the incidence rate was relatively high. Follow-up revealed a possible relationship between exacerbation of pre-existing colitis and treatment with rofecoxib. Hypotheses arising from signal generation require evaluation and cannot be taken as a conclusive evidence for clinical differences in the safety profiles of drugs.