Irinotecan-induced Mucositis Research Articles

Therapeutic effects of a lipid transfer protein isolated from Morinda citrifolia L. (noni) seeds on irinotecan-induced intestinal mucositis in mice.

This work aimed to evaluate the activity of a lipid transfer protein isolated from Morinda citrifolia L. seeds, McLTP1, on the development of intestinal mucositis following irinotecan administration. McLTP1 (0.5, 2, and 8 mg/kg, i.v.) was injected into mice 1h before irinotecan administration (75 mg/kg, i.p.; 4 days), and then for additional 6 days. Seven days after the first dose of irinotecan, diarrhea was assessed, and the intestine was removed for histological evaluation, assessment of intestinal over-contractility, measurement of myeloperoxidase (MPO), proinflammatory cytokines and chemokine (IL-1, IL-6, and KC levels - a murine homolog of human IL-8 chemokine), analysis of cyclooxygenase 2 (COX-2), nuclear factor kappa B (NF-κB), and nitric oxide synthase (iNOS) expression. At the two highest doses, McLTP1 administration decreased mortality and diarrhea. McLTP1 (8 mg/kg, i.v.) significantly prevented irinotecan-induced intestinal damage and led to a reduction in over-contractility of the intestinal muscle (p < 0.05). Moreover, McLTP1 decreased the MPO, IL-1β, IL-6, and KC levels by 74.7%, 42%, 92.9%, and 95.9%, respectively. Also, the expression of COX-2, NF-κB, and iNOS was reduced. Our study provides a potential new therapeutic for preventing irinotecan-induced mucositis, improved clinical parameters, and reduced inflammation.

Eosinophil plays a crucial role in intestinal mucositis induced by antineoplastic chemotherapy.

Mucositis is a major clinical complication associated with cancer treatment and may limit the benefit of chemotherapy. Leukocytes and inflammatory mediators have been extensively associated with mucositis severity. However, the role of eosinophils in the pathophysiology of chemotherapy-induced mucositis remains to be elucidated. Here, using GATA-1-deficient mice, we investigated the role of eosinophils in intestinal mucositis. There was marked accumulation of eosinophils in mice given irinotecan and eosinophil ablation inhibited intestinal mucositis. Treatment with Evasin-4, a chemokine receptor antagonist, reduced the recruitment of eosinophils and decreased irinotecan-induced mucositis. Importantly, Evasin-4 did not interfere negatively with the antitumour effects of irinotecan. Evasin-4 was of benefit for mice given high doses of irinotecan once Evasin-4-treated mice presented delayed mortality. Altogether, our findings suggest that Evasin-4may have significant mucosal-protective effects in the context of antineoplastic chemotherapy and may, therefore, be useful in combination with anticancer treatment in cancer patients.

Bifidobacterium longum subsp. longum 51A attenuates intestinal injury against irinotecan-induced mucositis in mice

Intestinal mucositis (IM) is a critical side-effect associated with antineoplastic therapy. Treatment available is only palliative and often not effective. However, alternative therapeutic strategies, such as probiotics, have attracted significant attention due to their immune-modulatory action in several diseases. Thus, the present study aims to elucidate the therapeutic potential of the probiotic strain Bifidobacterium longum 51A in a murine model of mucositis induced by irinotecan. Due to the scarcity of studies on dose-response and viability (probiotic vs paraprobiotic), we first evaluated which dose and cell viability would be most effective in treating mucositis. In this study, the oral pretreatment with viable B. longum 51A at a concentration of 1 × 109 CFU/mL reduced the daily disease activity index (p < 0.01), protected the intestinal architecture, preserved the length of the intestine (p < 0.05), and reduced intestinal permeability (p < 0.01), inflammation, and oxidative damage (p < 0.01) induced by irinotecan. Also, treatment with B. longum 51A increased the production of secretory immunoglobulin A (p < 0.05) in the intestinal fluid of mice with mucositis. Furthermore, B. longum 51A reversed the mucositis-induced increase in Enterobacteriaceae bacterial group in the gut (p < 0.01). In conclusion, these results showed that oral administration of B. longum 51A protects mice against intestinal damage caused by irinotecan, suggesting its use as a potential probiotic in therapy during mucositis.

The Protective Effect of Ethanolic Extract of Mentha spicata Against Irinotecan-Induced Mucositis in mice

Irinotecan induced-mucositis is an inflammatory event of intestine caused by an increase in concentration of active metabolite 7­ethyl­10-hydroxycamptothecin (SN­38) in the intestine. Irinotecan must first be converted by a carboxylesterase (CES) to the active metabolite (SN­38), which is subsequently glucuronidated by the hepatic enzyme to SN38G. The SN-38G is deconjugated in the intestine to SN-38 via ?-glucuronidase produced by the intestinal bacterial flora, which accounts for SN-38 delayed intestinal mucositis of irinotecan. To study the protective effect of mentha in irinotecan-induced mucositis, intestinal mucositis induced by I.P injection of irinotecan (75mg/Kg/day) for 4 days. Mentha ethanolic extract orally administered to mice for 7 days starting one day before irinotecan dose. Results showed that mentha ethanolic extract significantly decreased both jejunal tissue IL-1? (3.47±1.23 vs 6.5±0.36 ng/ml) and fecal ?-glucuronidase activity (79.78± 10.7 vs 120.6± 8.3 U) compared to model control group. Histopathological sections showed improvements in mucositis features in the mentha extract treated animals compared to the model control mice. As a conclusion, Mentha ethanolic extract has a protective effect on irinotecan-induced mucositis.

Ethylacetate fractional extract of Mentha spicata attenuates irinotecan‐induced mucositis in mice

Irinotecan induced‐mucositis is an inflammatory event of intestine that has negative impact on patient health and affect treatment efficacy. Irinotecan first metabolized in the liver by a carboxylesterase (CES) to the active cytotoxic metabolite (SN‐38), which subsequently glucuronidated by hepatic enzymes to the inactive metabolite SN38G. The SN‐38G undergo deconjugation in the intestine liberating the active SN‐38 via β‐glucuronidase produced by the intestinal bacterial flora. Consequently, SN‐38 triggers inflammation events characterized by delayed intestinal mucositis and diarrhea. This study aims to ameliorate irinotecan‐induced mucositis and diarrhea in mice model using ethylacetate fractional extraction of Mentha spicata(EAEMS), an edible widley consumed plant. Mice model of irinotecan‐induced mucositis and diarrhea produced by I.P injection of irinotecan (75mg/Kg/day) for 4 days. EAEMS administered orally (160mg/kg) twice daily for 7 days starting one day before irinite can dose. Diarrhae scores and mice body weight variation measured to assess the severity of mucositis and diarrhea. Jejunal IL‐1β and MPO measured as markers of intestinal inflammation. β‐glucuronidase activity in fecal pelletes were measured also. Compared to model control mice, results revealed that animals received EAEMS presented with significantly lower diarrhea scores and body weight loss. Furthermore, jejunal IL‐1β and MPO significantly reduced and associated with significant inhibition of fecal β‐glucuronidase activity in animals received EAEMS compared to model control mice. In conclusion, we showed for the first time that EAEMS has a protective effect against irinotecan‐induced mucositis and diarrhea, an effect suggested to be mediated by inhibition of bacterial β‐glucuronidase activity. This promising result might have a therapeutic application in cancer patients suffering from delayed‐onset diarrhea due to irinotecan treatment.Support or Funding InformationUniversity of Baghdad, College of PharmacyThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Irinotecan-Induced Mucositis Is Associated with Goblet Cell Dysregulation and Neural Cell Damage in a Tumour Bearing DA Rat Model.

Irinotecan-induced mucositis is a major oncological problem. Goblet cells secrete mucus, protecting the intestinal mucosa, with secretion altered during mucositis. The enteric nervous system is involved in regulating gut motility and secretion. The aim of this study was to determine whether enteric neural cells and goblet cells are altered following irinotecan treatment. Tumour-bearing Dark Agouti rats were administered a single dose of 175mg/kg of irinotecan intraperitoneally and 0.01mg/kg atropine subcutaneously. Experimental and untreated control rats were killed at times 6, 24, 48, 72, 96 and 120h after treatment. Jejunum and colon samples were formalin fixed. Haematoxylin and eosin staining, Alcian Blue-PAS staining, and immunohistochemistry with S-100 antibody (neural cell marker) were carried out. Statistical analyses were carried out using Kruskal-Wallis test with Dunns post test, Mann Whitney U test and nonlinear regression. Total goblet cells decreased at 72h compared with controls in the colon (p < 0.05). The percentage of cavitated goblet cells decreased compared to all other time points at 120h in the colon. The number of S-100 positive cells in the submucosal plexus decreased in the colon (p = 0.0046) and in the myenteric plexus of the jejunum and colon (p = 0.0058 and p = 0.0022, respectively), when comparing treated with control. Enteric ganglia in the myenteric plexus of the jejunum decreased at 24h and 96h. Irinotecan-induced mucositis is associated with increases in mucus secretion, and enteric neural cell change. These changes may contribute to the pathophysiology of mucositis through the dysregulation of neural signalling.

Irinotecan induces enterocyte cell death and changes to muc2 and muc4 composition during mucositis in a tumour-bearing DA rat model.

Irinotecan-induced mucositis is a major oncological problem. Goblet cells secrete mucus, protecting the intestinal mucosa, with secretion altered during mucositis. The enteric nervous system is involved in regulating gut motility and secretion. The aim of this study was to determine whether enteric neural cells and goblet cells are altered following irinotecan treatment. Tumour-bearing Dark Agouti rats were administered a single dose of 175mg/kg of irinotecan intraperitoneally and 0.01mg/kg atropine subcutaneously. Experimental and untreated control rats were killed at times 6, 24, 48, 72, 96 and 120h after treatment. Jejunum and colon samples were formalin fixed. Haematoxylin and eosin staining, Alcian Blue-PAS staining, and immunohistochemistry with S-100 antibody (neural cell marker) were carried out. Statistical analyses were carried out using Kruskal-Wallis test with Dunns post test, Mann Whitney U test, and nonlinear regression. Total goblet cells decreased at 72h compared with controls in the colon (p < 0.05). The percentage of cavitated goblet cells decreased compared to all other time points at 120h in the colon. The number of S-100-positive cells in the submucosal plexus decreased in the colon (p = 0.0046) and in the myenteric plexus of the jejunum and colon (p = 0.0058 and p = 0.0022, respectively), on comparing treated with control. Enteric ganglia in the myenteric plexus of the jejunum decreased at 24h and 96h. Irinotecan-induced mucositis is associated with increases in mucus secretion and enteric neural cell change. These changes may contribute to the pathophysiology of mucositis through the dysregulation of neural signalling.

Flavonoid-rich fraction of Bauhinia forficata Link leaves prevents the intestinal toxic effects of irinotecan chemotherapy in IEC-6 cells and in mice.

This study evaluated the effects of flavonoid-rich fraction from Bauhinia forficata leaves (FRF-BF), against intestinal toxicity induced by irinotecan. The leaves of this plant are used like tea in Brazilian folk medicine, and it is rich in flavonoids, mainly kaempferitrin. First, the chemopreventive effects of FRF-BF and kaempferitrin were evaluated in intestinal cells (IEC-6 cells) exposed to irinotecan. Next, the effects were evaluated against irinotecan-induced mucositis in mice. Lastly, melanoma was induced in C57BL/6 mice to evaluate FRF-BF interference on irinotecan antitumor activity. The results showed that FRF-BF and kaempferitrin exert no cytotoxic effects in IEC-6 cells and confirmed that pretreatment with FRF-BF and kaempferitrin displays chemoprotective effects against cytotoxicity induced by irinotecan. Interestingly, the FRF-BF (100mg/kg, p.o) reduced the intestinal motility in mice and attenuated parameters linked to irinotecan-induced intestinal mucositis, including diarrhea, histological damage, depletion of duodenal GSH, amount of TNF-α, and MPO activity in the small intestine. Also, FRF-BF does not interfere in the antitumor activity of irinotecan and exerted antitumoral activity in murine melanoma. In conclusion, FRF-BF (100mg/kg, p.o) presents promising pharmacological potential to prevent and attenuate the severity of intestinal mucositis during chemotherapy treatment, related to the presence of kaempferitrin.

Beneficial effects of anthocyanins from red cabbage (Brassica oleracea L. var. capitata L.) administration to prevent irinotecan-induced mucositis

Intestinal mucositis is a common side effect of Irinotecan (CPT-11). Anthocyanins (ACs) from red cabbage against CPT-11-induced mucositis were studied. Mice were given CPT-11 (75mg/kg, i.p. for 4days) and treated with ACs (50, 100mg/kg, i.g. for 7days). On day 8, diarrhea and leukocyte count in blood were assessed. Samples of intestine were obtained for morphometric analysis, myeloperoxidase (MPO), TBARS and GSH assay. The effects of ACs on cytoprotection and intestinal permeability were studied in Caco-2 cells. ACs effectively reversed the signs of intestinal injury, including MPO activity, length of ileum and colon, leukopenia, intestinal architecture, and quantity of ileum mucus. In vitro, pretreatment with ACs enhanced transepithelial electrical resistance (TER) and the expression of ZO-1. Furthermore, the protective effects of ACs were associated to modulate autophagy through mTOR pathway. In conclusion, ACs from red cabbage are candidate for supplementary therapy of CPT-11-induced mucositis.

Irinotecan-induced mucositis: the interactions and potential role of GLP-2 analogues

A common side effect of irinotecan administration is gastrointestinal mucositis, often manifesting as severe diarrhoea. The damage to the structure and function of the gastrointestinal tract caused by this cytotoxic agent is debilitating and often leads to alterations in patients' regimens, hospitalisation or stoppage of treatment. The purpose of this review is to identify mechanisms of irinotecan-induced intestinal damage and a potential role for GLP-2 analogues for intervention. This is a review of current literature on irinotecan-induced mucositis and GLP-2 analogues mechanisms of action. Recent studies have found alterations that appear to be crucial in the development of severe intestinal mucositis, including early apoptosis, alterations in proliferation and cell survival pathways, as well as induction of inflammatory cascades. Several studies have indicated a possible role for glucagon-like peptide-2 analogues in treating this toxicity, due to its proven intestinotrophic, anti-apoptotic and anti-inflammatory effects in other models of gastrointestinal disease. This review provides evidence as to why and how this treatment may improve mucositis through the possible molecular crosstalk that may be occurring in models of severe intestinal mucositis.

Cell adhesion molecules are altered during irinotecan-induced mucositis: a qualitative histopathological study

Chemotherapy-induced mucositis is characterised by damage to mucous membranes throughout the alimentary tract. This study aims to investigate the expression of cell adhesion molecules (CAMs) following treatment with irinotecan. Dark agouti rats received a single dose of 175mg/kg irinotecan and sacrificed at various time points after treatment. Picro-sirius red staining indicated an increase in collagen around crypts from 24h in both small and large intestinal regions and this diminished at the later time points. CAMs E-cadherin, P-selectin, E-selectin and integrin-α1 were examined using immunohistochemistry. E-cadherin was significantly elevated in jejunal crypts at the time of maximal tissue damage (48h), while it decreased at the healing phase (96h) in both jejunum and colon. P-selectin expression decreased significantly in the jejunum following irinotecan. Crypt expression of E-selectin was significantly elevated in the healing phase of mucositis (96h). Integrin-α1 expression was significantly altered during the time course in the villus (p=0.0032) and lamina propria (p=0.039). Irinotecan induced a significant alteration in CAM expression in the jejunum and colon. Changes in adhesion molecule expression may have a direct impact on the loss of mucosal layer integrity seen in mucositis.

Irinotecan- and 5-fluorouracil-induced intestinal mucositis: insights into pathogenesis and therapeutic perspectives.

Intestinal mucositis and diarrhea are common manifestations of anticancer regimens that include irinotecan, 5-fluorouracil (5-FU), and other cytotoxic drugs. These side effects negatively impact therapeutic outcomes and delay subsequent cycles of chemotherapy, resulting in dose reductions and treatment discontinuation. Here, we aimed to review the experimental evidence regarding possible new targets for the management of irinotecan- and 5-FU-related intestinal mucositis. A literature search was performed using the PubMed and MEDLINE databases. No publication time limit was set for article inclusion. Here, we found that clinical management of intestinal mucositis and diarrhea is somewhat ineffective at reducing symptoms, possibly due to a lack of specific targets for modulation. We observed that IL-1β contributes to the apoptosis of enterocytes in mucositis induced by 5-FU. However, 5-FU-related mucositis is far less thoroughly investigated with regard to specific molecular targets when compared to irinotecan-related disease. Several studies have proposed that a correlation exists between the intestinal microbiota, the enterohepatic recirculation of active metabolites of irinotecan, and the establishment of mucositis. However, as reviewed here, this association seems to be controversial. In addition, the pathogenesis of irinotecan-induced mucositis appears to be orchestrated by interleukin-1/Toll-like receptor family members, leading to epithelial cell apoptosis. IL-1β, IL-18, and IL-33 and the receptors IL-1R, IL-18R, ST2, and TLR-2 are potential therapeutic targets that can be modulated to minimize anticancer agent-associated toxicity, optimize cancer treatment dosing, and improve clinical outcomes. In this context, the pathogenesis of mucositis caused by other anticancer agents should be further investigated.

Saccharomyces cerevisiae UFMG A-905 treatment reduces intestinal damage in a murine model of irinotecan-induced mucositis.

Indigenous microbiota plays a crucial role in the development of several intestinal diseases, including mucositis. Gastrointestinal mucositis is a major and serious side effect of cancer therapy, and there is no effective therapy for this clinical condition. However, some probiotics have been shown to attenuate such conditions. To evaluate the effects of Saccharomyces cerevisiae UFMG A-905 (Sc-905), a potential probiotic yeast, we investigated whether pre- or post-treatment with viable or inactivated Sc-905 could prevent weight loss and intestinal lesions, and maintain integrity of the mucosal barrier in a mucositis model induced by irinotecan in mice. Only post-treatment with viable Sc-905 was able to protect mice against the damage caused by chemotherapy, reducing the weight loss, increase of intestinal permeability and jejunal lesions (villous shortening). Besides, this treatment reduced oxidative stress, prevented the decrease of goblet cells and stimulated the replication of cells in the intestinal crypts of mice with experimental mucositis. In conclusion, Sc-905 protects animals against irinotecan-induced mucositis when administered as a post-treatment with viable cells, and this effect seems to be related with the reduction of oxidative stress and preservation of intestinal mucosa.

The reduction of oxidative stress by nanocomposite Fullerol decreases mucositis severity and reverts leukopenia induced by Irinotecan

Irinotecan is a useful chemotherapeutic agent for the treatment of several solid tumors. However, this therapy is associated with side effects, including leukopenia and mucositis. Reactive oxygen species (ROS) activate inflammatory pathways and contribute to Irinotecan-induced mucositis. Fullerol is a nanocomposite with anti-oxidant properties that may reduce tissue damage after inflammatory stimuli. In this paper, the effects of Fullerol and mechanisms of protection were investigated in a model of Irinotecan-induced mucositis. Mucositis was induced by an injection of Irinotecan per 4 days in C57BL/6. Fullerol or a vehicle was injected every 12h. On day 7, the intestines were removed to evaluate histological changes, leukocyte influx, and the production of cytokines and ROS. Irinotecan therapy resulted in weight loss, an increased clinical score and intestinal injury. Treatment with Fullerol attenuated weight loss, decreased clinical score and intestinal damage. Irinotecan also induced increased ROS production in enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Fullerol treatment decreased production of ROS in the enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Irinotecan therapy also induced leukopenia in an ROS-dependent manner because leukopenia reverted in WT mice treated with Fullerol or Apocynin or in Gp91phox-/- mice. Mice treated with Irinotecan presented less melanoma tumor growth compared to the control group. Fullerol does not interfere in the anti-tumor action of Irinotecan. Fullerol has a great pharmacology potential to decreases the severity of mucositis and of leukopenia during chemotherapy treatment.

Serum-derived bovine immunoglobulin/protein isolate in the alleviation of chemotherapy-induced mucositis.

BackgroundGastrointestinal (GI) mucositis caused by chemotherapy is associated with diarrhoea and intestinal barrier disruption caused by apoptosis, immune dysfunction and microbiome alterations. Serum-derived bovine immunoglobulin/protein isolate (SBI) has been shown to manage HIV-associated enteropathy and irritable bowel syndrome with diarrhoea (IBS-D). We investigated in a rat model whether SBI was effective in alleviating symptoms of irinotecan-induced GI mucositis.MethodsAnimals were gavaged with 250 or 500 mg/kg of SBI twice daily for 4 days, before intraperitoneal administration of 200 mg/kg irinotecan. Twice daily gavaging of SBI continued for 6 days post-irinotecan. Animals were monitored for bodyweight changes and incidence of diarrhoea and clinical symptoms of stress. Tissues and blood samples were collected at necropsy 6 h, and 2, 4 and 6 days post-irinotecan. H&E-stained colon and jejunum were analysed for histological damage.ResultsThe overall incidence, severity and duration of diarrhoea, and clinical symptoms of mucositis were decreased in irinotecan-treated animals that had received SBI. Animals receiving 500 mg/kg SBI also tended to lose less bodyweight than animals treated only with irinotecan (P > 0.10). SBI-gavaged animals had less pronounced irinotecan-induced changes in neutrophil (P = 0.04959) and lymphocyte (P = 0.0035) levels, and lower tissue damage scores than those receiving irinotecan alone (P < 0.0001).ConclusionsTwice daily oral gavage of SBI was well-tolerated and reduced the incidence, severity and duration of irinotecan-induced mucositis. SBI was associated with less pronounced changes in inflammatory cell levels and tissue damage to colon and jejunum. Ongoing experiments aim to investigate the mechanisms of SBI-associated gastrointestinal protection.

Dark Agouti rat model of chemotherapy-induced mucositis: establishment and current state of the art.

Mucositis is a major oncological problem. The entire gastrointestinal and genitourinary tract and also other mucosal surfaces can be affected in recipients of radiotherapy, and/or chemotherapy. Major progress has been made in recent years in understanding the mechanisms of oral and small intestinal mucositis, which appears to be more prominent than colonic damage. This progress is largely due to the development of representative laboratory animal models of mucositis. This review focuses on the development and establishment of the Dark Agouti rat mammary adenocarcinoma model by the Mucositis Research Group of the University of Adelaide over the past 20 years to characterize the mechanisms underlying methotrexate-, 5-fluorouracil-, and irinotecan-induced mucositis. It also aims to summarize the results from studies using different animal model systems to identify new molecular and cellular markers of mucositis.

Serum-derived bovine immunoglobulin in the alleviation of irinotecan-induced mucositis.

166 Background: Gastrointestinal (GI) mucositis is associated with diarrhoea and intestinal barrier dysfunction caused by apoptosis, immune dysfunction, and microbiome alterations. Serum-derived bovine immunoglobulin (SBI) has been shown to ameliorate inflammation in colitis models, has been shown to improve HIV-induced enteropathy and nutritional status, and is being investigated in post-surgical recovery in oncology patients. We investigated in a rat model whether SBI was effective in alleviating symptoms of GI mucositis. Methods: Animals were gavaged with 250 or 500mg/kg of SBI twice daily, before intraperitoneal administration of 200mg/kg irinotecan on day 4, and for 6 days post-irinotecan. Animals were monitored for bodyweight and diarrhoea. Tissues were collected at necropsy 6, 48, 96 and 144 hours post-irinotecan. H&amp;E-stained colon and jejunum were analysed for histological damage. Results: The overall incidence, severity and duration of diarrhoea, and clinical symptoms of mucositis, were decreased in irinotecan-treated animals that had received SBI. Animals receiving 500 mg SBI/kg also tended to lose less bodyweight than animals treated only with irinotecan (P&gt;0.10). Animals receiving SBI had less pronounced irinotecan-induced changes in neutrophil levels (P≈0.02), and lower tissue damage scores than those receiving irinotecan alone (P&lt;0.0001). Conclusions: Twice-daily oral gavage of SBI was well-tolerated, and reduced the incidence, severity and duration of irinotecan-induced mucositis. SBI was associated with less pronounced changes in inflammatory cell levels and intestinal tissue damage. Ongoing experiments aim to explore the mechanisms of SBI-associated gastrointestinal protection.

Inflammasome Activation Is Reactive Oxygen Species Dependent and Mediates Irinotecan-Induced Mucositis through IL-1β and IL-18 in Mice

Irinotecan is a useful chemotherapeutic for the treatment of various cancers. Irinotecan treatment is associated with mucositis, which clearly limits the use of the drug. Mechanisms that account for mucositis are only partially known. This study assessed mechanisms and the role of inflammasome activation in irinotecan-induced mucositis. Mucositis in mice was induced by irinotecan injection in C57BL/6 wild-type, gp91phox(-/-), il-18(-/-), casp-1(-/-), and asc(-/-) mice once a day for 4 consecutive days. In some experiments, mice received apocynin to inhibit NADPH oxidase (NOX), IL-1 receptor antagonist, or IL-18 binding protein to prevent activation of IL-1 and IL-18 receptors, respectively. Mice were euthanized 7 days after the beginning of irinotecan treatment, and small intestines were collected for analysis. Irinotecan treatment resulted in increased IL-1β and IL-18 production in ileum and NOX-2-dependent oxidative stress. gp91phox(-/-) and apocynin-treated mice had diminished oxidative stress and less severe mucositis. Furthermore, treatment with apocynin decreased caspase-1 activation and IL-1β and IL-18 production in the ileum. asc(-/-) and casp-1(-/-) mice also had less intestinal injury and decreased IL-1β and IL-18 production. Finally, both the absence of IL-18 and IL-1β resulted in reduced inflammatory response and attenuated intestinal injury. NOX-2-derived oxidative stress mediates inflammasome activation and inflammasome-dependent production of IL-1β and IL-18, which mediate tissue injury during irinotecan-induced mucositis in mice.

Serum-derived immunoglobulin and the alleviation of irinotecan-induced mucositis.

e20717 Background: Gastrointestinal (GI) mucositis is associated with diarrhoea and intestinal barrier dysfunction caused by apoptosis, immune dysfunction, and microbiome alterations. Serum-derived...

Selection of Housekeeping Genes for Gene Expression Studies in a Rat Model of Irinotecan-Induced Mucositis

Background/Aims: Mucositis is the term used to describe damage caused by chemotherapy to mucous membranes of the alimentary tract. RT-PCR has recently been utilised to determine the molecular events that occur in mucositis. As this method relies on the use of a validated endogenous control, this study aims to validate commonly used housekeeping genes in an irinotecan-induced mucositis model. Methods: Rats were administered irinotecan and sacrificed at different time points, in particular 1, 24, 72 and 144 h following treatment. Histopathological damage was assessed by haematoxylin and eosin staining. RT-PCR was used to evaluate the expression of 11 housekeeping genes. Expression stability was determined by the Normfinder program. Matrix metalloproteinase 2 was used as a target gene to validate the appropriateness of the top-ranking housekeeping gene. Results: For normalisation to multiple housekeeping genes, the most stable combination across all time points in the jejunum was Ywhaz/UBC and in the colon UBC/β-actin. SDHA and GAPDH were the most variable genes in the jejunum and colon where they were 4.4 and 3.2 fold upregulated following irinotecan, respectively. Conclusions: For normalisation of irinotecan-induced mucositis gene expression studies, a combination of Ywhaz/UBC and UBC/β-actin should be used in the jejunum and colon, respectively. UBC is the most favourable if restricted to a single housekeeping gene across all time points.