Carlos Wagner Souza Wanderley

Targeted inhibition of IL‐18 attenuates irinotecan‐induced intestinal mucositis in mice

Intestinal mucositis is a common side‐effect of irinotecan‐based cancer chemotherapy regimens. This mucositis is associated with cytokine activation and NO synthesis. Production of IL‐18 is up‐regulated in patients suffering from inflammatory bowel disease. Therefore, we have investigated the role of IL‐18 in the pathogenesis of irinotecan‐induced intestinal mucositis.

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

AbstractPurposeIntestinal 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.MethodsA literature search was performed using the PubMed and MEDLINE databases. No publication time limit was set for article inclusion.ResultsHere, 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.ConclusionsIL-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.

The Adaptor Protein Myd88 Is a Key Signaling Molecule in the Pathogenesis of Irinotecan-Induced Intestinal Mucositis

Intestinal mucositis is a common side effect of irinotecan-based anticancer regimens. Mucositis causes cell damage, bacterial/endotoxin translocation and production of cytokines including IL–1 and IL–18. These molecules and toll-like receptors (TLRs) activate a common signaling pathway that involves the Myeloid Differentiation adaptor protein, MyD88, whose role in intestinal mucositis is unknown. Then, we evaluated the involvement of TLRs and MyD88 in the pathogenesis of irinotecan-induced intestinal mucositis. MyD88-, TLR2- or TLR9-knockout mice and C57BL/6 (WT) mice were given either saline or irinotecan (75 mg/kg, i.p. for 4 days). On day 7, animal survival, diarrhea and bacteremia were assessed, and following euthanasia, samples of the ileum were obtained for morphometric analysis, myeloperoxidase (MPO) assay and measurement of pro-inflammatory markers. Irinotecan reduced the animal survival (50%) and induced a pronounced diarrhea, increased bacteremia, neutrophil accumulation in the intestinal tissue, intestinal damage and more than twofold increased expression of MyD88 (200%), TLR9 (400%), TRAF6 (236%), IL–1β (405%), IL–18 (365%), COX–2 (2,777%) and NF-κB (245%) in the WT animals when compared with saline-injected group (P<0.05). Genetic deletion of MyD88, TLR2 or TLR9 effectively controlled the signs of intestinal injury when compared with irinotecan-administered WT controls (P<0.05). In contrast to the MyD88-/- and TLR2-/- mice, the irinotecan-injected TLR9-/- mice showed a reduced survival, a marked diarrhea and an enhanced expression of IL–18 versus irinotecan-injected WT controls. Additionally, the expression of MyD88 was reduced in the TLR2-/- or TLR9-/- mice. This study shows a critical role of the MyD88-mediated TLR2 and TLR9 signaling in the pathogenesis of irinotecan-induced intestinal mucositis.

Bothrops jararacussu snake venom-induces a local inflammatory response in a prostanoid- and neutrophil-dependent manner.

Local tissue reactions provoked by Bothrops venoms are characterized by edema, hemorrhage, pain, and inflammation; however, the mechanisms of tissue damage vary depending upon the species of snake. Here, we investigated the mechanisms involved in the local inflammatory response induced by the Bothrops jararacussu venom (BjcuV). Female Swiss mice were injected with either saline, BjcuV (0.125-8 μg/paw) or loratadine (an H1 receptor antagonist), compound 48/80 (for mast cell depletion), capsaicin (for C-fiber desensitization), infliximab (an anti-TNF-α antibody), indomethacin (a non-specific COX inhibitor), celecoxib (a selective COX-2 inhibitor) or fucoidan (a P- and L-selectins modulator) given before BjcuV injection. Paw edema was measured by plethysmography. In addition, paw tissues were collected for the measurement of myeloperoxidase activity, TNF-α and IL-1 levels, and COX-2 immunoexpression. The direct chemotactic effect of BjcuV and the in vitro calcium dynamic in neutrophils were also investigated. BjcuV caused an edematogenic response with increased local production of TNF-α and IL-1β as well as COX-2 expression. Both edema and neutrophil migration were prevented by pretreatment with indomethacin, celecoxib or fucoidan. Furthermore, BjcuV induced a direct in vitro neutrophil chemotaxis by increasing intracellular calcium. Therefore, BjcuV induces an early onset edema dependent upon prostanoid production and neutrophil migration.

α-Phellandrene, a cyclic monoterpene, attenuates inflammatory response through neutrophil migration inhibition and mast cell degranulation

AIMS We aimed to investigate the modulating effect of α-phellandrene on neutrophil migration and mast cell degranulation processes. MAIN METHODS Male Wistar rats or Swiss mice were treated p.o. with vehicle (3% Tween 80, p.o.), α-phellandrene (50, 100, or 200mg/kg, p.o.), or dexamethasone (0.5mg/kg, p.o.) 1h before carrageenan injection. Then, the neutrophil migration in 6-day-old air pouches or peritoneal cavities. The leukocyte rolling and adhesion were measured in real time and assessed by intravital microscopy. ELISA was used to detect TNF-α and IL-6 in peritoneal lavage. Compound 48/80-induced mast cell degranulation was assessed in mesenteric rat tissues. KEY FINDINGS In all the tested doses, α-phellandrene prevented carrageenan-induced neutrophil accumulation (P<0.05). As detected by intravital microscopy, α-phellandrene also inhibited leukocyte rolling and adhesion, as well as significantly inhibited the production of the pro-inflammatory cytokines TNF-α and IL-6. Moreover, the degranulation of compound 48/80-induced mast cells was also inhibited by α-phellandrene (P<0.001). SIGNIFICANCE These results suggest that α-phellandrene plays an important role as an anti-inflammatory agent through neutrophil migration modulation and mast cell stabilization.

Role of regulatory T cells in irinotecan-induced intestinal mucositis

Abstract Intestinal mucositis (IM) is a common side effect of irinotecan‐based chemotherapy. The involvement of inflammatory mediators, such as TNF‐&agr;, IL1‐&bgr;, IL‐18 and IL‐33, has been demonstrated. However, the role of adaptive immune system cells, whose activation is partially regulated by these cytokines, is yet unknown. Thus, we investigated the role of regulatory T cells (Tregs) in irinotecan‐induced IM. C57BL/6 mice were injected with saline or irinotecan (75 mg kg− 1, i.p.), once a day for 4 days, and euthanized at day 1, 3, 5 or 7 following the first dose of irinotecan. For Treg depletion, the mice were pretreated with a low single dose of cyclophosphamide (100 mg kg− 1, i.p). Intestinal lamina propria lymphocytes were harvested and purified by Percoll gradient. Treg and Th17 cells were identified by flow cytometry. Blood leukocyte count was obtained and ileum samples were collected for histopathological analysis and myeloperoxidase assay. IM caused an accumulation of Tregs and Th17 cells over time. Treg depletion exacerbated intestinal damage, diarrhea, neutrophil infiltration and animal mortality, despite a reduction in Th17 cell number. The frequency of other Th cells increased and was positively correlated with neutrophil infiltration. Tregs showed a negative correlation with neutrophils and the frequency of non‐regulatory Th cells. In conclusion, Tregs are important in the control of intestinal damage induced by irinotecan, and their depletion showed a deleterious effect on IM. Activation of these cells appears to be a compensatory mechanism for intestinal inflammation. Graphical abstract Figure. No caption available.

Neutrophils contribute to the pathogenesis of hemorrhagic cystitis induced by ifosfamide

Abstract Ifosfamide (IFO) is an antineoplastic drug that is commonly used to treat gynecological and breast cancers. Hemorrhagic cystitis (HC) is a common side effect associated with IFO injection, which courses with neutrophil accumulation and affects 6–50% of patients depending on dose intensity. Here, we investigated the role of neutrophils in this inflammatory process. Female Swiss mice (n = 8/group) were injected with saline, IFO (400 mg/kg, i.p.), fucoidan (a P‐ and L‐selectins inhibitor, 100 mg/kg, i.v.) or IFO + fucoidan (1–100 mg/kg) alone or combined with mesna (80 mg/kg i.p.). Another group of mice received anti‐Ly6G antibody (500 &mgr;g/mouse, once daily for 2 days) for neutrophil depletion before IFO injection. In another experimental setting, animals received granulocyte colony‐stimulating factor (G‐CSF, 400 &mgr;g/kg), IFO (200 mg/kg), G‐CSF (25–400 &mgr;g/kg, for 5 days) + IFO (200 mg/kg, i.p.) or fucoidan + G‐CSF + IFO. Bladder injury was evaluated 12 h after IFO injection. IFO 400 mg/kg significantly increased visceral hyperalgesia, bladder edema, hemorrhage, vascular permeability, MPO, IL‐1&bgr; and IL‐6 tissue levels, and COX‐2 immunostaining and expression versus the saline group (P < 0.05). Conversely, fucoidan (100 mg/kg) significantly attenuated these parameters compared to IFO‐injected mice (P < 0.05). Additionally, fucoidan potentiated mesna protective effect when compared with IFO + mesna group (P < 0.05). Accordingly, neutrophil depletion with anti‐Ly6G reduced inflammatory parameters and bladder injury compared to IFO (P < 0.05). In contrast, G‐CSF enhanced IFO (200 mg/kg)‐induced HC, which was significantly attenuated by treatment with fucoidan (P < 0.05). Therefore, neutrophils contribute to the pathogenesis of HC. HighlightsNeutrophils contribute to the pathogenesis of hemorrhagic cystitis induced by ifosfamide.Filgastrim (a granulocyte colony stimulating factor) induces neutrophilia.Filgastrim enhances ifosfamide‐induced hemorrhagic cystitis, which is prevented by fucoidan, a P‐ and L‐selectin inhibitor.P‐ and L‐selectins are promising pharmacological targets to inhibit neutrophil migration during hemorrhagic cystitis.

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil

PURPOSE To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis. METHODS Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation. RESULTS Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1β between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886. CONCLUSIONS Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.

Bases da Resposta Inflamatória do Trato Gastrintestinal

A inflamacao e uma resposta vascular, celular e humoral, responsavel pelo processo de defesa dos organismos vivos ante agentes agressores. Essa resposta fisiologica e resultante da acao coordenada entre o sistema imunologico e o tecido no qual ocorreu a lesao. Por incorporar varios mecanismos biologicos, como a formacao de edema, fagocitose, angiogenese, fibroplasia, liberacao de mediadores quimicos, alem de outros fatores, a inflamacao passou a ser entendida como um processo, proveniente de uma soma de eventos, que, de acordo com o tempo de evolucao e as caracteristicas patologicas envolvidas, pode ser classificada em in - flamacao aguda ou cronica (KUMAR, 2010)