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Tumor hypoxia may compromise the results of chemotherapy for treating colorectal cancer because it stimulates angiogenesis and the release of tumor growth factors. Hyperbaric oxygen (HBO) supplementation may potentiate the effects of chemotherapy in such cases. This study aimed to assess the effect of HBO therapy combined with chemotherapy on the treatment of colorectal cancer in mice. C57BL6 mice were submitted to the intrarectal instillation of N-methyl-N-nitrosoguanidine (MNNG) and treated with 5-fluorouracil (5FU) and/or HBO therapy. The MNNG group presented the highest dysplastic crypt rate. The 5FU + HBO group presented the highest rate of apoptotic cells per dysplastic crypt. The 5FU group presented the highest expression of hypoxia-inducible factor-1 alpha and CD44. HBO therapy increased the effect of 5FU on the treatment of the experimental colorectal neoplasia in mice.
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Neoplasias Colorrectales , Fluorouracilo , Oxigenoterapia Hiperbárica , Ratones Endogámicos C57BL , Animales , Fluorouracilo/farmacología , Ratones , Neoplasias Colorrectales/terapia , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/tratamiento farmacológico , Masculino , Antimetabolitos Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Receptores de Hialuranos/metabolismo , Terapia Combinada , Metilnitronitrosoguanidina/farmacologíaRESUMEN
BACKGROUND: Combinations of immune checkpoint inhibitors (ICI) with platinum-based chemotherapy (PlatinumCT) or with another ICI in the first-line setting for patients with metastatic urothelial carcinoma (mUC) have mixed results. METHODS: Records were searched electronically from January 2019 to January 2024. A meta-analysis was performed to evaluate OS, progression-free survival (PFS), and overall response rate (ORR). RESULTS: Immune-based combinations were associated with an OS (HR: 0.75; 95% CI: 0.61-0.92; p < 0.001; I2= 84.1%) and PFS benefit in the intention-to-treat population (HR: 0.67; 95%CI: 0.51-0.89; p < 0.001; I2 = 89.7%). There was no ORR improvement with immune-based combinations (HR: 1.36; 95% CI:0.84-2.20; p < 0.001; I2 = 92.6%). CONCLUSION: This systematic review and study-level meta-analysis demonstrated that the immune-based combinations in first-line treatment for patients with mUC are associated with survival benefit.
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Inhibidores de Puntos de Control Inmunológico , Humanos , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Metaanálisis en Red , Neoplasias Urológicas/tratamiento farmacológico , Neoplasias Urológicas/patología , Neoplasias Urológicas/mortalidad , Neoplasias Urológicas/inmunología , Carcinoma de Células Transicionales/tratamiento farmacológico , Carcinoma de Células Transicionales/patología , Carcinoma de Células Transicionales/mortalidad , Neoplasias de la Vejiga Urinaria/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/mortalidad , Resultado del TratamientoRESUMEN
RET fusions occur in 1-2% of non-small cell lung cancer. Selpercatinib and pralsetinib are selective RET inhibitors with significant improvement of outcome in patients with tumor harboring RET fusion; however, resistance mechanisms appear frequently, mainly driven by MAPK pathway bypass, secondary RET mutations, or in 5% via MET amplification. Co-inhibition of RET and MET is a compelling strategy for overcoming MET-dependent resistance to RET inhibitors and potentially other inhibitors. To our knowledge, this is the first report of a novel ISOC1-RET fusion lung cancer with a durable complete response to selpercatinib, with resistance via MET amplification, which was overcome by the successful combination of selpercatinib and capmatinib.
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Background: Radiation proctitis affects 1-20% of cancer patients undergoing radiation exposure due to pelvic malignancies, including prostate, gynecological and rectum cancers. The patients manifest rectal discomfort, pain, discharge, and bleeding. Notably, the efficacy of prophylactic measures remains controversial due to the lack of adequate animal models that mimic this condition. Objective: The present study then aimed to develop a murine model of high-dose-rate (HDR) brachytherapy-induced proctitis. Material/Methods: C57BL/6 male mice were subjected to HDR (radiation source: iridium-192 [Ir-192]) through a cylindrical propylene tube inserted 2 cm far from the anal verge into the rectum. The animals received radiation doses once a day for three consecutive days (fractions of 9.5 Grays [Gy]), 3.0 mm far from the applicator surface. The sham group received only the applicator with no radiation source. The survival rate was recorded, and a colonoscopy was performed to confirm the tissue lesion development. Following euthanasia, samples of the rectum were collected for histopathology, cytokines dosage (IL-6 and KC), and immunohistochemical analysis (TNF-α and COX-2). Results: HDR significantly reduced animals' survival ten days post first radiation exposure (14% survival vs. 100% in the non-irradiated group). Day seven was then used for further investigation. Mice exposed to radiation presented with rectum injury confirmed by colonoscopy and histopathology (P < 0.05 vs. the control group). The tissue damage was accompanied by an inflammatory response, marked by increased KC and IL-6 tissue levels, and immunostaining for TNF-α and COX-2 (P < 0.05 vs. control group). Conclusions: We established a novel animal model of actinic proctitis induced by HDR brachytherapy, marked by inflammatory damage and low animal mortality.
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Background and purpose: The discovery of chemical substances with carcinogenic properties has allowed the development of several experimental models of colorectal cancer (CRC). Classically, experimental models of CRC in mice have been evaluated through clinical or serial euthanasia. The present study aims to investigate the role of low endoscopy in the analysis of carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Methods: Thirty C57BL6 mice were divided into two groups: a control group with fifteen animals that underwent rectal instillation of saline solution on day 0 and a carcinogen group with fifteen animals that underwent a 100 mg/kg MNNG rectal instillation on day 0. In both groups, low endoscopies were performed on weeks 4 and 8. We used a validated endoscopic scoring system to evaluate the severity of colitis and colorectal tumor. Euthanasia was carried out at week 12. Results: We observed higher inflammation scores (p <0.001) and a higher number of tumors (p <0.05) in the MNNG group than the control group, both at weeks 4 and 8. A worsening of inflammation scores from the first to the second endoscopy was also noticeable in the MNNG group. There were no bowel perforations related to the procedure, and there was one death in the control group. Conclusion: Low endoscopy in experimental animals allows safe macroscopic evaluation of colorectal carcinogenesis without the need for euthanasia.
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Metilnitronitrosoguanidina/toxicidad , Neoplasias Experimentales/inducido químicamente , Neoplasias del Recto/inducido químicamente , Administración Rectal , Animales , Carcinogénesis/inducido químicamente , Carcinogénesis/patología , Colonoscopía/métodos , Femenino , Humanos , Metilnitronitrosoguanidina/administración & dosificación , Ratones , Neoplasias Experimentales/diagnóstico , Neoplasias Experimentales/patología , Neoplasias del Recto/diagnóstico , Neoplasias del Recto/patología , Recto/diagnóstico por imagen , Recto/efectos de los fármacos , Recto/patologíaRESUMEN
BACKGROUND: Previous data have reported that the growth of established tumors may be facilitated by postsepsis disorder through changes in the microenvironment and immune dysfunction. However, the influence of postsepsis disorder in initial carcinogenesis remains elusive. METHODS: In the present work, the effect of postsepsis on inflammation-induced early carcinogenesis was evaluated in an experimental model of colitis-associated colorectal cancer (CAC). We also analyzed the frequency and role of intestinal T regulatory cells (Treg) in CAC carcinogenesis. RESULTS: The colitis grade and the tumor development rate were evaluated postmortem or in vivo through serial colonoscopies. Sepsis-surviving mice (SSM) presented with a lower colonic DNA damage, polyp incidence, reduced tumor load, and milder colitis than their sham-operated counterparts. Ablating Treg led to restoration of the ability to develop colitis and tumor polyps in the SSM, in a similar fashion to that in the sham-operated mice. On the other hand, the growth of subcutaneously inoculated MC38luc colorectal cancer cells or previously established chemical CAC tumors was increased in SSM. CONCLUSION: Our results provide evidence that postsepsis disorder has a dual effect in cancer development, inhibiting inflammation-induced early carcinogenesis in a Treg-dependent manner, while increasing the growth of previously established tumors.
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Colitis/complicaciones , Neoplasias del Colon/patología , Modelos Animales de Enfermedad , Inflamación/complicaciones , Sepsis/complicaciones , Linfocitos T Reguladores/inmunología , Microambiente Tumoral/inmunología , Animales , Colitis/inmunología , Colitis/patología , Neoplasias del Colon/etiología , Citocinas/metabolismo , Femenino , Inflamación/patología , Ratones , Ratones Endogámicos C57BL , Sepsis/inmunología , Sepsis/patología , Transducción de SeñalRESUMEN
PURPOSE: Anticancer-drug efficacy seems to involve the direct interaction with host immune cells. Although topoisomerase I (Top I) inhibitors have been suggested to block LPS-evoked inflammation, the interaction between these drugs and toll-like receptor 4 (TLR4) is unaddressed. METHODS: SN-38, the active metabolite of the Top I inhibitor irinotecan, and TLR4 interaction was assessed using the in vitro luciferase nuclear factor-κB reporter assay, neutrophil migration to murine air-pouch, in silico simulation, and the thermal shift assay (TSA). Topotecan was used as a positive anti-inflammatory control. RESULTS: Non-cytotoxic concentrations of SN-38 attenuated LPS (a TLR4 agonist)-driven cell activation without affecting peptidoglycan (a TLR2 agonist)-activating response. Similarly, topotecan also prevented LPS-induced inflammation. Conversely, increasing concentrations of LPS reversed the SN-38 inhibitory effect. In addition, SN-38 abrogated LPS-dependent neutrophil migration and reduced TNF-α, IL-6, and keratinocyte chemoattractant levels in the air-pouch model, but failed to inhibit zymosan (a TLR2 agonist)-induced cell migration. A two-step molecular docking analysis indicated two potential binding sites for the SN-38 in the MD-2/TLR4 complex, the hydrophobic MD-2 pocket (binding energy of - 8.1 kcal/mol) and the rim of the same molecule (- 6.9 kcal/mol). The topotecan also bound to the MD-2 pocket. In addition, not only the lactone forms, but also the carboxylate conformations of both Top I inhibitors interacted with the MD-2 molecule. Furthermore, the TSA suggested the interaction of SN-38 with MD-2. CONCLUSIONS: Therefore, SN-38 inhibits acute inflammation by blocking LPS-driven TLR4 signaling. This mechanism seems to be shared by other Top I inhibitors.
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Inflamación/tratamiento farmacológico , Irinotecán/uso terapéutico , Receptor Toll-Like 4/genética , Inhibidores de Topoisomerasa I/uso terapéutico , Animales , Humanos , Irinotecán/farmacología , Masculino , Ratones , Inhibidores de Topoisomerasa I/farmacologíaRESUMEN
Neurodegenerative diseases (NDs) are a group of chronic, progressive disorders characterized by the gradual loss of neurons that affect specific regions of the brain, which leads to deficits in specific functions (e.g., memory, movement, cognition). The mechanism that drives chronic progression of NDs remains elusive. Among the proposed underlying pathophysiological mechanisms, aggregation and accumulation of misfolded proteins and neuroinflammation have been credited to contribute to extensive neural loss. Therapeutic agents that confer neuroprotection by downregulating these shared characteristics could therefore have beneficial effects on a wide range of NDs. In this regard, a commonly used antibiotic, doxycycline (Doxy), has been shown to reduce the progression and severity of disease in different experimental models of neurodegeneration by counteracting these common features. This review will focus on the effects reported for Doxy regarding its neuroprotective properties, the "off-target" effects, thereby supporting its evaluation as a new therapeutic approach for diseases associated with a neurodegeneration.
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Doxiciclina/administración & dosificación , Encefalitis/tratamiento farmacológico , Enfermedades Neurodegenerativas/tratamiento farmacológico , Fármacos Neuroprotectores/administración & dosificación , Animales , Encéfalo/efectos de los fármacos , Ensayos Clínicos como Asunto , Encefalitis/complicaciones , Humanos , Enfermedades Neurodegenerativas/complicaciones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Agregación Patológica de Proteínas/tratamiento farmacológicoRESUMEN
Neurodegenerative diseases (NDs) are a group of chronic, progressive disorders characterized by the gradual loss of neurons that affect specific regions of the brain, which leads to deficits in specific functions (e.g., memory, movement, cognition). The mechanism that drives chronic progression of NDs remains elusive. Among the proposed underlying pathophysiological mechanisms, aggregation and accumulation of misfolded proteins and neuroinflammation have been credited to contribute to extensive neural loss. Therapeutic agents that confer neuroprotection by downregulating these shared characteristics could therefore have beneficial effects on a wide range of NDs. In this regard, a commonly used antibiotic, doxycycline (Doxy), has been shown to reduce the progression and severity of disease in different experimental models of neurodegeneration by counteracting these common features. This review will focus on the effects reported for Doxy regarding its neuroprotective properties, the "off-target" effects, thereby supporting its evaluation as a new therapeutic approach for diseases associated with a neurodegeneration.
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Neurodegenerative diseases (NDs) are a group of chronic, progressive disorders characterized by the gradual loss of neurons that affect specific regions of the brain, which leads to deficits in specific functions (e.g., memory, movement, cognition). The mechanism that drives chronic progression of NDs remains elusive. Among the proposed underlying pathophysiological mechanisms, aggregation and accumulation of misfolded proteins and neuroinflammation have been credited to contribute to extensive neural loss. Therapeutic agents that confer neuroprotection by downregulating these shared characteristics could therefore have beneficial effects on a wide range of NDs. In this regard, a commonly used antibiotic, doxycycline (Doxy), has been shown to reduce the progression and severity of disease in different experimental models of neurodegeneration by counteracting these common features. This review will focus on the effects reported for Doxy regarding its neuroprotective properties, the "off-target" effects, thereby supporting its evaluation as a new therapeutic approach for diseases associated with a neurodegeneration.
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Wnt/ß-catenin signaling, a highly conserved pathway through evolution, regulates key cellular functions including proliferation, differentiation, migration, genetic stability, apoptosis, and stem cell renewal. The Wnt pathway mediates biological processes by a canonical or noncanonical pathway, depending on the involvement of ß-catenin in signal transduction. ß-catenin is a core component of the cadherin protein complex, whose stabilization is essential for the activation of Wnt/ß-catenin signaling. As multiple aberrations in this pathway occur in numerous cancers, WNT-directed therapy represents an area of significant developmental therapeutics focus. The recently described role of Wnt/ß-catenin pathway in regulating immune cell infiltration of the tumor microenvironment renewed the interest, given its potential impact on responses to immunotherapy treatments. This article summarizes the role of Wnt/ß-catenin pathway in cancer and ongoing therapeutic strategies involving this pathway.
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Antineoplásicos/farmacología , Inmunoterapia , Terapia Molecular Dirigida , Proteínas de Neoplasias/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Proteínas Wnt/antagonistas & inhibidores , Vía de Señalización Wnt/efectos de los fármacos , beta Catenina/antagonistas & inhibidores , Aciltransferasas/antagonistas & inhibidores , Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Comunicación Celular/efectos de los fármacos , Ensayos Clínicos como Asunto , Humanos , Inmunoterapia Adoptiva , Macrófagos/efectos de los fármacos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de Neoplasias/fisiología , Neoplasias/inmunología , Estudios Observacionales como Asunto , Subgrupos de Linfocitos T/inmunología , Tanquirasas/antagonistas & inhibidores , Escape del Tumor/efectos de los fármacos , Escape del Tumor/inmunología , Microambiente Tumoral , Proteínas Wnt/fisiología , Proteína Wnt-5a/agonistas , beta Catenina/fisiologíaRESUMEN
Sepsis, an overwhelming inflammatory response syndrome secondary to infection, is one of the costliest and deadliest medical conditions worldwide. Neutrophils are classically considered to be essential players in the host defense against invading pathogens. However, several investigations have shown that impairment of neutrophil migration to the site of infection, also referred to as neutrophil paralysis, occurs during severe sepsis, resulting in an inability of the host to contain and eliminate the infection. On the other hand, the neutrophil antibacterial arsenal contributes to tissue damage and the development of organ dysfunction during sepsis. In this review, we provide an overview of the main events in which neutrophils play a beneficial or deleterious role in the outcome of sepsis.
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Cistite hemorrágica (CH) induzida por ifosfamida (IFO) é uma importante complicação clínica em pacientes com câncer. Atualmente, mesna e hiper-hidratação são utilizadas como profilaxia, a despeito de ainda ser observada CH através de cistoscopia e histopatologia mesmo com essas medidas. A participação de interleucina-1 (IL-1) e fator de necrose tumoral (TNF) na patogênese da CH provê alvos para o tratamento dessa doença. Assim, esse trabalho objetivou avaliar o efeito protetor do antagonista do receptor da IL-1 (anakinra) e do anticorpo anti-TNF-alfa (infliximabe) nas respostas inflamatórias, nociceptivas e funcionais da CH experimental induzida por IFO em camundongos. Foram utilizados camundongos Swiss, C57BL6, IL-1R-/-, CASP1-/-, TNFR1-/-, TNFR1/R2-/-. Os animais WT foram submetidos ao tratamento com anakinra 100 mg/kg i.p. ou infliximabe 5 mg/kgi.p. ou salina i.p., foram tratados 1h após com IFO 400 mg/kg i.p., e 12 h após a IFO foi realizado o sacrifício, com excisão das bexigas para avaliaçãomacroscópica, histopatológica, permeabilidade vascular, mieloperoxidase, contratilidade, cistometrografia e citometria de fluxo para neutrófilos e macrófagos. Alguns animais, antes do sacrifício, foram submetidos a avaliação de nocicepção visceral. Anakinra foi capaz de atenuar hemorragia, edema, infiltrado neutrofílico, hipernocicepção visceral e disfunção vesical...
Hemorrhagic cystitis (HC) induced by ifosfamide (IFO) is an importantclinical complication in patients with cancer. Despite prophylaxis, HC isobserved. The role of interleukin-1 (IL-1) and tumor necrosis factor (TNF) in the pathogenesis of HC provides targets for treatment. Thus, this study aimed to evaluate the protective effect of the IL-1 receptor antagonist (anakinra) and anti-TNF-alpha antibody (infliximab) in experimental HC-induced by IFO in mice. Swiss , C57BL6 , IL -1R-/-, CASP1-/-, TNFR1-/-, TNFR1/R2-/-mice were used. Animals were submitted to pre-treatment with anakinra 100 mg/ kg, ip or infliximab 5 mg/ Kg, ip, or saline ip, 1h after, they were treated with IFO 400 mg/ kg ip, and 12 h after IFO injection they were killed. Then, it was performed resection of the bladder for macroscopic and histopathological evaluation, vascular permeability assay, myeloperoxidase assay, muscle contractility, cistometrogram and flow cytometry to neutrophils andmacrophages. Some animals prior to death, were subjected to evaluation of visceral nociception. Anakinra was able to attenuate hemorrhage, edema, neutrophil infiltration, visceral hypernociception and bladder dysfunction...
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Humanos , Cistitis , Quimioterapia , Ifosfamida , Proteína Antagonista del Receptor de Interleucina 1 , Anticuerpos MonoclonalesRESUMEN
Introdução: O câncer colorretal (CCR) é a terceira neoplasia mais diagnosticada no mundo. A doença inflamatória intestinal é uma importante causa de CCR com patogênese atrelada à inflamação crônica. A sepse é uma doença grave que modifica a resposta imune do hospedeiro. Objetivou-se estudar se animais sobreviventes à sepse apresentam alteração na iniciação tumoral e crescimento tumoral do CCR. Material e métodos: Camundongos C57Bl6 machos foram submetidos ao modelo de ligadura e punção do ceco (CLP), e após 15 dias, os sobreviventes e um grupo controle receberam azoximetano (AOM, 10 mg/kg, i.p.) e 3 ciclos de 5 dias de dextran sulfato de sódio (DSS 2%, ad libitum) nos dias 20-25, 40-45, 60-65 pós-CLP. Foi avaliada a colite e o desenvolvimento de tumores por colonoscopia. Foram quantificadas citocinas nos dias 0 12, 52 e 65 e de células T reguladoras (Treg) nos dias 12 e 65. Dois grupos de animais C57 receberam ciclofosfamida (CYP) (100 mg/kg, i.p.) e dois grupos de animais com expressão do receptor de toxina diftérica (DTX) sob regulação do gene Foxp3 receberam DTX (0,5 mg/animal, i.p.) antes do protocolo AOM/DSS. Outro grupo de animais, foi submetido posteriormente à CLP após AOM/DSS, bem como um grupo de animais foi injetado células de CCR murino (MC38luc) 105 células no subcutâneo e outro grupo, 106 células no baço no 15 dias pós-CLP. Resultados: Animais sobreviventes à sepse apresentaram redução da colite, além de menor incidência, número de tumores e carga tumoral que animais controle. Os animais pós-sepse tiveram menor produção de IFN-γ nos cólon no dia 12, de IL-1ß, TNF, IL-6, IL-17, KC e MIG dias 12 e 65, e IL-33, TGF e GM-CSF no dia 65 quando comparados a animais controle. Além disso, animais pós-sepse apresentaram maior quantidade de Treg no D15, contudo nos dias 12 e 65 observou-se um aumento significativo dessas células nos animais controle comparado ao pós-sepse. Curiosamente, animais pós-sepse que receberam CYP e DTX apresentaram colite e tumores de maneira semelhante aos animais controle. Por outro lado, camundongos pós-sepse tratados previamente com AOM/DSS apresentaram aumento na carga tumoral 30 dias após a CLP quando comparados aos controles. Além disso, no modelo de tumor subcutâneo e esplênico, foi observado maior crescimento tumoral em animais pós-sepse em comparação aos controles. Conclusões: A sepse promove inibição da inflamação intestinal murina e do CCR associado à colite, de maneira dependente de células Treg.
Introduction: Colorectal cancer (CRC) is the third most diagnosed neoplasm in the world. Inflammatory bowel disease is an important cause of CRC with pathogenesis linked to chronic inflammation. Sepsis is a life-threatening disease that modify the host immune response. We aimed to study whether sepsis-surviving mice showed alterations of colorectal cancer initiation and tumor progression. Materials and methods: C57Bl6 male mice were submitted to cecal ligation and puncture (CLP) model, and after 15 days, sepsis-surviving mice and one control group received azoxymethane (AOM, 10 mg/kg, ip) and dextran sodium sulfate (DSS 2%, ad libitum, 3 cycles of 5 days) on days 20-25, 40-45, 60-65 post-CLP. Colitis and tumor development were evaluated by colonoscopy. Cytokines were quantified on days 0, 12, 52 and 65 by Milliplex and Treg cells on days 12 and 65 by flow cytometry. Two groups of C57 animals received cyclophosphamide (CYP) (100 mg/kg, ip), and two groups of animals expressing diphtheria toxin (DTX) receptor under regulation of Foxp3 received DTX (0.5 mg/animal, ip) before the AOM/DSS protocol. Another animal cohort was submitted to CLP after receiving AOM/DSS, as well as, two other groups were injected with murine CRC cells (MC38luc) 105 cells subcutaneously or 106 cells intra-splenically 15 days post-CLP. Results: Sepsis-surviving animals showed reduced colitis, besides lower incidence, number of tumors and tumor load than control animals. Sepsis-surviving animals have lower production of IFN-γ in the colon on day 12, and of IL-1ß, TNF, IL-6, IL-17, KC and MIG on days 12 and 65, in addition to IL-33, TGF and GM-CSF on day 65 than control animals. In addition, post-sepsis mice had a higher amount of Treg on D15, however on days 12 and 65 a significant increase of these cells occurs in control animals compared to post-sepsis. Interestingly, post-sepsis animals receiving CYP and DTX developed colitis and tumors in a similar pattern as control animals. Conversely, post-sepsis mice previously submitted to OM/DSS showed an increase in tumor load 30 days after CLP when compared to controls. Furthermore, in the subcutaneous and intra-splenic model, it was observed increased tumor growth in post-sepsis animals when compared to the controls. Conclusions: Sepsis promotes inhibition of murine intestinal inflammation and colitis-associated CRC in a Treg dependent manner.
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Animales , Neoplasias Colorrectales , Linfocitos T Reguladores , Colitis , Sepsis , Modelos Animales , MacrófagosRESUMEN
PURPOSE: To design a novel model to study Cobalt-60 (Co-60)-induced radiation mucositis and to describe the pathways involved in its development. MATERIALS AND METHODS: Hamsters' cheeks were treated with Co-60 radiation (10, 20, 30 or 35 Gy). Three days later, oral mucosa scarification was performed with a needle. The animals were euthanized at day 13 (D + 13) after irradiation. Gross and microscopic alterations were evaluated by a new score system that we developed. Also, neutrophil infiltration, tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-10, inducible nitric oxide synthase (iNOS), nitric oxide (NO) and nitrite were assessed in oral mucosa. We also tried to establish the roles of TNF-α and IL-1ß and iNOS in our model using pharmacological approaches with pentoxiphylline (PTX) and aminoguanidine (AMG), respectively. RESULTS: We found that a single administration of 35 Gy of Co-60, followed by mechanical scratches 3 days later, induced oral mucositis in hamsters. Animals with mucositis lost weight and had a survival median of 13 days, the time at which peak inflammation occurs. We noticed increased levels of NO, iNOS, TNF-α and IL-1ß and a reduced concentration of IL-10. PTX partially prevented the mucositis phenotype by reducing the levels of inflammatory mediators and iNOS expression. Additionally, AMG, a selective inhibitor of iNOS, reduced Co-60-induced oral mucositis through reducing NO production. CONCLUSION: We described a novel model of megavoltage radiation-induced oral mucositis in hamsters. TNF-α, IL-1ß and NO seem to play a role in the pathophysiology of this model.
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Citocinas/metabolismo , Óxido Nítrico/metabolismo , Traumatismos Experimentales por Radiación/etiología , Traumatismos Experimentales por Radiación/metabolismo , Estomatitis/etiología , Estomatitis/metabolismo , Animales , Radioisótopos de Cobalto/efectos adversos , Cricetinae , Modelos Animales de Enfermedad , Guanidinas/farmacología , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Mediadores de Inflamación/metabolismo , Interleucina-1beta/metabolismo , Masculino , Mesocricetus , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II/metabolismo , Pentoxifilina/farmacología , Peroxidasa/metabolismo , Traumatismos Experimentales por Radiación/inmunología , Radioterapia de Alta Energía/efectos adversos , Estomatitis/inmunología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
PURPOSE: Intestinal mucositis and the closely associated diarrhea are common costly side effects of irinotecan. Cytokine modulators, such as thalidomide and pentoxifylline, are found capable of attenuating intestinal mucositis progression. Nitric oxide (NO) seems to be a key mediator of the antineoplastic drug toxicity. The aim of this study was to investigate the role of NO on the pathogenesis of intestinal mucositis, as well as the participation of cytokines upon inducible nitric oxide synthase (iNOS) expression in irinotecan-induced intestinal mucositis. METHODS: iNOS-knockout (iNOS(-/-)) and C57BL/6 (WT, wild type) animals (n = 5-6) were given either saline or irinotecan (60 mg/kg i.p for 4 days), with or without pretreatment with aminoguanidine (50 mg/kg s.c.), thalidomide (60 mg/kg s.c), infliximab (5 mg/kg i.v.), or pentoxifylline (1.7 mg/kg s.c). On day 5, diarrhea was assessed, and following euthanasia, proximal intestinal samples were obtained for myeloperoxidase (MPO) and iNOS activity, morphometric analysis, western blot and immunohistochemistry to iNOS, cytokine dosage, and for in vitro evaluation of gut contractility. RESULTS: Irinotecan induced severe diarrhea and intestinal smooth muscle over-contractility, accompanied with histopathological changes. Additionally, increased MPO and iNOS activity and iNOS immunoexpression were found in WT animals treated with irinotecan. The rise in MPO, smooth muscle over-contractility, and diarrhea were abrogated in aminoguanidine-treated and iNOS(-/-) mice. Moreover, through western blot, we verified that infliximab and pentoxifylline significantly inhibited irinotecan-induced iNOS expression. In addition, cytokine concentration was found only partially decreased in irinotecan-treated iNOS(-/-) mice when compared with wild-type animals that were given irinotecan. CONCLUSIONS: This study suggests a role of nitric oxide in the pathogenesis of irinotecan-induced intestinal mucositis and also provides evidence for the participation of cytokines on iNOS induction.