The hunt for biomarkers for anti-VEGF agent bevacizumab is ongoing since last decade with no success. Identifying robust biomarkers for stratifying patients and for monitoring response is important for the future use of bevacizumab in breast cancer. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) analysis and genome wide gene expression analysis are two promising approaches to understand the molecular mechanisms and search for biomarker of anti-angiogenic therapy. Firstly, with the retrospective pilot study, a close link between DCE-MRI findings and the molecular mechanisms assisting cancer survival and metastasis was established. Secondly, the prospective window of opportunity study conducted using single cycle of bevacizumab given before neoadjuvant chemotherapy and by performing detailed pharmacodynamic analyses with DCE-MRI and gene expression before and two weeks after bevacizumab had shown a wide variation in responses to bevacizmab both at genomic and imaging level. A close link between changes in DCE-MRI and the changes in gene expression profile was further established suggesting DCE-MRI has potential to serve as non-invasive biomarkers of antiangiogenic therapy. Tumours with high baseline values of forward transfer constant K^trans showed the maximum response as assessed by DCE-MRI after bevacizumab. By performing biopsy after single cycle of bevacizumab, the changes in genes related to immune response, metabolism and cell signalling were observed that gives a useful insight into mechanisms governing response and resistance to bevacizumab. Also the certain gene expression changes observed with post bevacizumab biopsies, such as down regulation of endothelial cell specific molecule-1 (ESM1), cyclin E1 (CCNE1) and up regulation of pyruvate dehydrogenase kinase 1 (PDK1), cyclic GMP-inhibited phosphodiesterase B (PDE3B) could be helpful in decision-making about future therapy with bevacizumab at an early stage. This study has suggested that using bevacizumab in combination with other targeted agents could overcome resistance.

Neuroblastoma, the most common extracranial solid tumor of childhood, is a heterogeneous tumor. In some patients, the tumor can go into spontaneous regression and disappear whereas other patients have rapidly growing tumors with a poor prognosis. The overall long-term survival rate in patients with high-risk neuroblastoma is less than 30%, indicating the need for new treatment strategies. Angiogenesis inhibition hampers the formation of new blood vessels, thereby limiting the tumors’ metabolic exchange. Neuroblastoma is rapidly growing and high tumor angiogenesis has been associated with poor outcome. Therefore, the aim of this thesis was to investigate the effect of novel treatment modalities for angiogenesis inhibition on high-risk neuroblastoma xenografts. For that purpose, we used subcutaneous mouse models and characterized orthotopic mouse models for high-risk neuroblastoma. We found that xenotransplantation of neuroblastoma cells into the adrenal gland of SCID and SCID beige mice resulted in orthotopic tumors resembling clinical neuroblastoma in respect to tumor site, growth and spread. Using contrast-enhanced ultrasound, we observed that the receptor tyrosine kinase inhibitor SU11248 reduced orthotopic neuroblastoma growth and spread by reducing tumor angiogenesis. In subcutaneous xenografts for high-risk neuroblastoma, valuable for studies requiring continuous assessment of tumor volume, we demonstrated that immune-neutralizing VEGF with the anti-VEGF antibody bevacizumab significantly reduced neuroblastoma growth. Finally, we found that formulations of the chemotherapeutic drug GMX1778 inhibited angiogenesis and induced tumor regression in a dose dependent manner without host toxicity. We showed that relapsing tumors remained responsive to GMX-therapy without accelerated growth or induced drug resistance. In conclusion, SU11248, bevacizumab, and formulations of the active compound GMX1778 may become useful for treating high-risk neuroblastoma.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第12879号 / 論農博第2806号 / 新制||農||1028(附属図書館) / 学位論文||H26||N4878(農学部図書室) / 31597 / (主査)教授 植田 和光, 教授 植田 充美, 教授 矢﨑 一史 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Le traitement médical du cancer colorectal a connu ces dernières années d'importantes avancées avec l'arrivée notamment des thérapies ciblées anti-angiogéniques et anti-EGFR. Néanmoins ces molécules ne bénéficient pas à tous les patients et il est à ce jour impossible de bien individualiser leur utilisation. Mon travail de thèse s'est donc intéressé à d'une part à identifier de nouveaux facteurs prédictifs de réponse en particulier au bévacizumab, d'autre part à rechercher et antagoniser de nouvelles cibles ou des mécanismes participant à la résistance aux molécules disponibles notamment pour les patients non répondeurs aux anti-EGFR. Premièrement, nous avons montré que le sorafenib améliorait l'activité anti-tumorale de l'irinotecan in vitro et in vivo sur des lignées cellulaires de cancer du colon rendues résistantes au SN38 indépendamment de leur statut K-ras. Pour expliquer ce phénomène, nous avons mis en évidence que le sorafenib inhibait la pompe d'efflux ABCG2 et favorisait l'accumulation intra-cellulaire de l'irinotecan et donc sa cytotoxicité. De plus, nous avons vérifié la faisabilité d'une telle association chez l'homme et confirmé son efficacité chez des patients K-ras mutés lourdement prétraités. Deuxièmement, nous avons développé un nouveau score radiologique objectif combinant l'évolution de la taille et la densité tumorale normalisée à celle du foie qui pourrait être utilisé comme marqueur de substitution pour déterminer précocément les bons répondeurs à une chimiothérapie à base de bevacizumab chez des patients présentant des métastases hépatiques. / The medical treatment of colorectal cancer has made significant progresses in recent years including the arrival of targeted therapies: anti-angiogenic and anti-EGFR. However, these molecules don't benefit all patients and their use is not well personalized. My thesis is therefore aimed, on one hand, to identify new predictors of response especially to bevacizumab and, on the other hand, to find and antagonize new targets or mechanisms involved in chemo-resistance, especially for K-ras mutated patients. Firstly, we have showed that sorafenib improved the anti-tumoral activity of irinotecan, both in vitro and in vivo, in SN-38 resistant colon adenocarcinoma cell lines independently of their K-ras status. To explain this phenomenon, we have demonstrated that sorafenib inhibited the efflux pump ABCG2 and promoted the intracellular accumulation of irinotecan and thus its cytotoxicity. In addition, we have checked the feasibility of such an association in human and confirmed its efficacy in K-ras mutated heavily pretreated patients. Secondly, we have developed a new objective radiological score combining both tumor size and density normalized to the liver that could be used as objective surrogate markers to determine early good responders after bevacizumab-containing chemotherapy in patients with colorectal liver metastases.

Les Malformations Artérioveineuses sont des lésions vasculaires évolutives. Elles peuvent avoir des conséquences neurologiques lourdes liées au risque hémorragique élevé qui est leur mode de révélation le plus fréquent. Le développement de meilleurs outils d’imagerie a beaucoup amélioré le diagnostic de ces lésions et a permis une meilleure compréhension de leur interaction avec le tissu cérébral. Néanmoins, Leur 4eme dimension et leur évolution restent encore obscures.Par ailleurs, les traitements actuels (embolisation, microchirurgie, chirurgie stéréotaxique) sont associés à des risques de morbidité et mortalité importants.Pour ces raisons, nous avons travaillé sur un traitement potentiel peu invasif: des agents antiangiogéniques. Un modèle porcin simplifié a été élaboré consistant en l’occlusion unilatérale de l’artère carotide primitive et externe par voie endovasculaire. Ce modèle a présenté des preuves d’angiogénèse et des modifications anatomopathologiques proches de celles des MAVc humaines. Le Bevacizumab, un anticorps monoclonal pour le VEGF, a été administré in situ sur ce modèle. Les résultats ont montré que l’agent antiangiogénique altère l’angiogénèse sur les specimens histologiques. L’épaisseur de la paroi des vaissaux a été stabilisée après l’injection de Bevacizumab mais le volume des retia est demeuré identique montrant que le volume dépend de l’angiogénèse mais probablement également du flux / Brain arteriovenous malformations are dynamic, evolving vascular lesions. They present high morbidity rates due to hemorrhagic presentation that is the most frequent symptom at onset and potentially high mortality rates .Up to date imaging techniques has greatly facilitated the diagnosis of these lesions and the better understanding of their relation to adjacent brain tissue. However, it remains still a challenge to define their four dimensional nature and its consequences, a fact that can actually optimize their treatment. Embolization, surgery and stereotactic radiosurgery that are currently used in the treatment of AVMs carry also significant morbi-mortality risks. For this reason, a potential minimally invasive treatment with antiangiogenic agents was tested. A swine model was firstly created using the animal’s rete mirabile and performing an endovascular occlusion of one common and external carotid artery. This simplified model presented evidence of angiogenesis and histologic findings that are also observed in human AVMs compared to a control group. Secondly, Bevacizumab that is a monoclonal antibody to vascular endothelial growth factor, was in situ administered on this model. The results showed that the antiangiogenic agent tampered angiogenesis on histologic samples by stabilizing the wall thickness of the arteries but it did not have any effect on volume that is probably depending on flow and not only on angiogenesis.

Objetivo: Avaliação funcional (acuidade visual e sensibilidade ao contraste) e morfológica da retina de pacientes com edema macular diabético (EMD) tratados com bevacizumabe intravítreo e controle glicêmico optimizado durante 24 semanas de acompanhamento. Projeto: Estudo prospectivo intervencionista, randomizado e controlado. Métodos: Quarenta e um olhos de 34 pacientes com diabetes mellitus tipo 2 e EMD com Hemoglobina glicada (HbA1c) <= 11% receberam injeções de bevacizumabe intravítreo (BIV) com controle glicêmico optimizado nas semanas 0, 6, 12 e 18 (grupo 1; n=21); ou receberam simulação de BIV com controle glicêmico optimizado na semana 0 e 6 e, posteriormente, BIV com controle glicêmico optimizado na semana 12 e 18 (Grupo 2; n=20). Mudanças na sensibilidade ao contraste (SC), na acuidade visual (AV) e na espessura foveal (EF) medida por Tomografia de coerência óptica (TCO) foram comparadas antes do início do tratamento e nas semanas 2, 6, 12, 14, 18 e 24. A análise laboratorial do controle sistêmico foi comparada também no início e nas semanas 12 e 24. Resultados: O estudo mostrou AV e EF significativamente melhores em 24 semanas em ambos os grupos. Na 24ª semana, a média da SC melhorou no grupo 1 de 1,14±0,36logCS para 1,33±0,24logCS (P=0,002) e, também, no grupo 2 de 1,11±0,29 para 1,26±0,23logCS (P = 0,004) em 24 semanas, sem diferença significativa entre eles (P = 0,52). Houve uma redução média de 0,78% nos níveis de HbA1c (8,28±1,29% para 7,5±1,20%; P < 0,001) em 24 semanas. As maiores diferenças entre os grupos foram detectadas entre o pré-tratamento e a segunda semana, onde a EF diminuiu rapidamente no grupo 1 em comparação ao grupo 2 (116±115 vs. 17±71?m, respectivamente; P < 0,01). Em 12 semanas, as medidas já não foram estatisticamente significativas (variação da EF = grupo 1 91±184?m vs. grupo 2 62±152?m; P = 0.72). No pré-tratamento, houve correlação significativa entre SC e AV (r = -0,70; P < 0,001) e também entre SC e EF (r = -0,63; P < 0,001) que se manteve em 24 semanas. Conclusão: O uso do bevacizumabe intravítreo associado ao controle glicêmico optimizado melhorou significativamente a função visual, incluindo a sensibilidade ao contraste dos olhos com EMD. No entanto, o controle glicêmico optimizado isolado também se mostrou eficiente durante 12 semanas / Purpose: Functional (visual acuity and contrast sensitivity) and morphological evaluation of the retina of patients with diabetic macular edema (DME) treated with intravitreal bevacizumab and optimized glycemic control on 24-week followup. Project: Prospective, interventional, randomized controlled trial. Methods: Forty-one eyes of 34 patients with type 2 diabetes mellitus and DME with hemoglobin A1c (HbA1c) <= 11% received injections of intravitreal bevacizumab (IVB) with optimized glycemic control (group 1; n=21) at week 0, 6, 12 and 18; or received IVB simulation with optimized glycemic control at week 0 and 6 and, after three months, IVB with optimized glycemic control at week 12 and 18 (Group 2; n=20). Mean Change in contrast sensitivity (CS), best corrected visual acuity (BCVA) and central foveal thickness (CFT) - as measured by optical coherence tomography (OCT) were compared at baseline, and at weeks 2, 6, 12, 14, 18 and 24. A laboratory analysis of systemic control was also compared at baseline and at weeks 12 and 24. Results: The study showed that BCVA and CFT were significantly better in both groups at 24 weeks. Mean CS also improved significantly in group 1 from 1.14±0.36 to 1.33±0,24logCS (P=0,002) and also in group 2 from 1.11±0.29 to 1.26±0.23logCS (P=0,004) at 24 weeks, with no significant difference between them (P = 0.52). There was a mean reduction of 0.78% in HbA1c levels (8,28±1,29 to 7,5±1,20%; P < 0,001) at 24 weeks. The major differences between both groups were detected between the baseline and the second week, whem CFT promptly decreased in group 1 compared to group 2 (116±115 ?m vs. 17±71 ?m; P < 0,01). At 12 weeks, the measures were no longer statistically significant (variation of CFT = group 1 91±184 ?m vs. group 62±152 ?m, P = 0.72). At baseline, there was meaningful correlation between CS and BCVA (r = -0,70; P < 0,001) and also between CS and CFT (r = -0.63; P < 0.001) that remained at 24 weeks. Conclusion: The use of intravitreal bevacizumabe associated with optimized glycemic control improved significantly the visual function, including contrast sensitivity in eyes with DME. However, optimized glycemic control alone also shown to be efficient at 12 weeks

L’objectif principal de ce travail de thèse a été de caractériser les effets de l’anti-VEGF Bevacizumab (Avastin) sur le réseau vasculaire tumoral in vivo, au cours du temps, à l’aide du modèle de la chambre dorsale chez la souris nude. Les images du réseau vasculaire tumoral acquises par microscopie intravitale ont été analysées par un algorithme de traitement d’images développé au sein de notre équipe, permettant de mettre en évidence les modifications morphologiques induites par le traitement et d’isoler des paramètres discriminants de la « normalisation » vasculaire, par comparaison à un réseau vasculaire sain. La période de « normalisation » vasculaire détectée par notre outil a été confortée par l’analyse de la fonctionnalité des vaisseaux sanguins au cours du temps, in vivo et par une analyse immunohistochimique des vaisseaux sanguins tumoraux et du tissu tumoral. A travers des essais préliminaires in vivo, en regard des résultats de ce travail concernant une fenêtre de "normalisation", nous avons cherché à vérifier l'hypothèse d'un bénéfice d'un traitement anti-VEGF préalablement à la thérapie photodynamique (PDT) sur des tumeurs de glioblastome xénogreffées en sous-cutané et en chambre dorsale. L'efficacité de la PDT est décrite comme étant dépendante d'une d'oxygénation tumorale suffisante et d'une distribution maximale de l'agent photosensibilisant au coeur des tumeurs. Parallèlement à ces travaux, nous avons cherché en équipe pluridiscilinaire à développer un modèle mathématique de la réponse au bevacizumab à partir de données biologiques réelles obtenues sur le même modèle in vivo et permettant pour l'avenir de simuler les réponses à différentes doses et différentes durées de traitement, toujours à des fins d'optimisation des protocoles thérapeutiques / The main aim of this work was to characterize the effects of the anti-VEGF Bevacizumab (Avastin) on the tumor vascular network, in vivo, over time, thanks to the skin fold chamber model on the nude mouse. Images of the vascular network obtained using intravital microscopy were analyzed par a dedicated image processing algorithm developed within our research team, allowing to highlight the morphological modifications induced by the treatment and to isolate discriminating parameters of the vascular "normalization", by comparison to healthy vascular networks. Le vascular "normalization" period detected with our tool was comforted by the analysis of the functionality of the blood vessels over time, in vivo and by an immunohistochemical analysis of the blood vessels and of the tumor tissue. In preliminary in vivo experiments, we tried to verify the hypothesis of the benefits of an anti-VEGF treatment prior to photodynamic therapy (PDT) on glioblastoma xenografts implanted subcutaneously or in the skin fold chamber. The efficacy of PDT is described as being dependent on tumor oxygenation and on the distribution of the photosensitizing agent within the tumor. In paralel to this work, we tried as a pluridisciplinary team to develop a mathematical model of the tumor response to bevacizumab using biological data obtained on the same in vivo model et that will allow in the future to simulate the response for different doses and different treatment durations, for the optimization of therapeutic protocols

Angiogenese ist an physiologischen Vorgängen wie der Embryogenese und der Wundheilung, aber auch bei pathologischen Abläufen wie bei Neoplasien und der Makula Degeneration beteiligt. Im Bereich des Tissue Engineering ist sie ebenfalls unersetzlich und ausschlaggebend für den Erfolg einer Gewebetransplantation. In dieser Studie wurde an 40 männliche Charles Lewis-Ratten das arteriovenöse (AV-) Loop-Modell angewandt, um spontane Angiogenese unter Einfluss wachstumshemmender Faktoren in vivo zu untersuchen. Der AV-Loop wurde in einer mit Fibrin gefüllten Teflonkammer gebettet. Für die statistische Auswertung wurde der Student t-Test mit ungepaarten Stichproben angewandt und das Signifkanzniveau betrug α=0,05. Multiple Testungen wurden nach der Bonferroni-Holm-Methode angepasst. In der Anfangsphase der Studie wurde der zeitliche Verlauf der AV-Loop assoziierten Angiogenese an 16 Tieren untersucht. Es wurde ein signifikanter Anstieg der Gefäßfläche über einen Zeitraum von 5 (n=2), 10 (n=3) und 15 Tagen (n=3) beobachtet und ebenfalls eine signifikant höhere Gefäßanzahl an Tag 15 im Vergleich zu Tag 5. Acht Tiere konnten nicht in die Studie miteingeschlossen werden infolge von Thrombosierungen des Loops. Diese erwartete Verlustrate trat aufgrund Lernkurve dieses komplexen mikrochirurgischen Modells, insbesondere zu Beginn des Projektes, auf. In der zweiten Phase der Studie wurde die Neoangiogenese auf drei unterschiedliche Verfahren gehemmt. Die Implantationszeit betrug bei allen Gruppen 15 Tage. In der ersten Gruppe (n = 6) wurde ein Inhibitor des Wachstumfaktors VEGF (vascular endothelial growth factor) intravenös appliziert, nämlich der monoklonale Antikörper Bevacizumab. Hier konnte ein signifikanter Unterschied zur Kontrollgruppe (n = 6) bei der Gefäßfläche (94 432 ± 17 903 μm2 gegenüber 268 682 ± 63 575 μm2) und ebenfalls bei der Gefäßdichte (18 ± 5 Gefäße pro mm2 versus 40 ± 9 Gefäße pro mm2 in der Kontrollgruppe) gemessen werden. Dieser Befund ließ darauf schließen, dass die Neovaskularisation durch VEGF vermittelt wurde. Die direkte Bestrahlung von 2 Gy auf den venösen Graft in der zweiten Versuchsgruppe (n = 7) löste eine signifikante Verringerung von Gefäßanzahl (311 ± 73), -fläche (43 137 ± 10 225 μm2) und –dichte (15 ± 7 Gefäße pro mm2) im Vergleich zur Kontrollgruppe (776 ± 123, 268 682 ± 63 575 μm2 und 40 ± 9 Gefäße pro mm2) aus. Dieses Verfahren hatte somit starken Einfluss auf den Reifeprozess der Neoangiogenese. Bei der Kombinationsgruppe (Bevacizumab und Bestrahlung, n = 5) konnte nur bei der Gefäßfläche ein signifikant geringerer Unterschied in der Angiogenese erhoben werden. Dies ließ vermuten, dass das hier zu findende physiologische und somit geordnete Gefäßwachstum nicht auf diese hemmende Methode anspricht, wie es bei chaotischen Tumorgefäßsystemen der Fall ist und der vermutete Synergismus ausbleibt. Zusätzlich wurde im Zuge dieser Studie ein standardisiertes Auswertungsprogramm etabliert. Dabei handelt es sich um ein selbstentwickeltes Computerprogramm, das nicht nur die hier gesammelten aber auch 2-D-Aufnahmen anderer Angiogenese-Modelle benutzerunabhängig und standardisiert evaluieren kann. Zusammenfassend kann gesagt werden, dass das AV-Loop-Modell sich ausgezeichnet für die Untersuchung der Angiogenese im gesunden Gewebe eignet. Es bietet die Möglichkeit verschiedene angiogene und anti-angiogene Faktoren zu applizieren sowie deren Einfluss auf eine physiologische Neovaskularisation zu beobachten. / Angiogenesis is evident in both physiological and pathological processes in the body. It is involved in events of embryogenesis and in wound healing as well as in neoplastic growth and macula degeneration. In the field of Tissue Engineering neovascularisation plays an irreplaceable role and determines the result of the transplantation. Here, an arterio-venous loop (AV-loop) model embedded in fibrin- filled teflon chambers in 40 Charles Lewis rats was applied to conduct in vivo investigations of the physiological processes of vessel growth in healthy tissue and to understand neovascularisation under the impact of anti-angiogenic factors such as monoclonal anti-bodies and ionizing radiation (IR). For statistical analysis the unpaired t-test was applied with a significance level of α = 0,05. Multiple testing was adapted according to the Bonferroni-Holm method. At the beginning of the study the AV-loop induced angiogenesis was examined on 16 animals and consecutively characterized. A significant increase in vessel area was observed over a time frame of 5 (n=2), 10 (n=3) and 15 days (n=3). Additionally the vessel count has increased significantly at day 15 in comparison to day 5. Eight of the animals had to be excluded due to thrombosis of the loop, which was expected due to the complex microsurgical model, especially at the onset of the project. In the second phase of the study three different anti-angiogenic procedures were investigated. Time of implantation was 15 days. In group one (n = 6) the monoclonal antibody of VEGF (vascular endothelial growth factor) named Bevacizumab was applied intravenously. As a result a significant lower vessel area (94 432 ± 17 903 μm2) and density (18 ± 5 vessels per mm2) could be measured in comparison to the control group (n = 6; 268 682 ± 63 575 μm2 respectively 40 ± 9 vessels per mm2). We concluded from these results that angiogenesis was mediated by VEGF. In comparison to the controlgroup direct IR of 2 Gy led in group two (n = 7) to a significant decrease in vessel number (311 ± 73 versus 776 ± 123), area (43137±10225μm2 versus 268682±63575μm2) and density (15±7 versus 40±9 vessels per mm2). Therefore this procedure has an obvious impact on the vessel maturation. In the combined group (n = 5) of both anti-angiogenic procedures (anti- VEGF and IR) a significant decrease was only evident in the vessel area. We assumed that this physiological and accordingly organized angiogenesis does not respond to the applied inhibiting methods, as it is observed in tumor vessel growth. Additionally, an evaluation program was established with the goal of designing a user-independent and standardized computer program to measure 2-D-images of both this and other angiogenesis models. In summary the AV-loop presents a proficient model to investigate angiogenesis in healthy tissue. It offers a variety of possibilities to apply pro- and anti-angiogenic factors and to examine their impact in vivo.

Introdução: A pleurodese química é rotineiramente utilizada para o controle de derrames pleurais recidivantes. O fator de crescimento do endotélio vascular (VEGF) é uma citocina produzida em resposta à inflamação pleural induzida por esclerosantes e possui papel essencial na angiogênese e na fibrose pleural. O anticorpo monoclonal bevacizumab bloqueia a ação do VEGF, sendo utilizado no tratamento de algumas neoplasias malignas com o objetivo de inibir a angiogênese e a progressão tumoral. Os efeitos do bevacizumab sobre o processo inflamatório pleural e sobre a pleurodese induzida por talco e nitrato de prata ainda não foram totalmente descritos. Objetivo: Caracterizar a influência do anticorpo monoclonal anti-VEGF, bevacizumab, nas fases precoce e tardia da pleurodese induzida pelo talco ou nitrato de prata. Métodos: Foram estudados 152 coelhos que receberam injeção intrapleural de talco (n=76) ou nitrato de prata (n=76). Metade dos animais em cada grupo recebeu injeção intravenosa de bevacizumab 30 minutos antes do agente esclerosante. Após a injeção intrapleural de talco ou nitrato de prata, 5 animais em cada grupo foram sacrificados em 1, 2, 3, 4, 7, 14 e 28 dias. Um subgrupo de 12 animais recebeu azul de Evans 1 hora antes do sacrifício realizado no terceiro dia, para análise de permeabilidade pleural. Em todos os animais, o líquido pleural obtido foi quantificado, sendo realizadas análises bioquímica, citológica e imunológica. A cavidade pleural foi avaliada macroscopicamente através de escore para quantificação de aderências. Microscopicamente, a pleura visceral foi analisada por escore para o grau de inflamação e fibrose; a densidade vascular foi avaliada por imunohistoquímica (anti fator VIII) e o espessamento pleural e a quantidade de colágeno (fibras colágenas coradas pelo método de picrosirius) mensurados através de um sistema de análise de imagem. Análise Estatística: Os resultados estão expressos em média e erro padrão (SEM). Comparações entre os grupos foram feitas utilizando-se o teste t não-pareado ou Mann-Whitney, sendo considerado significativo um valor de p inferior a 0,05. Resultados: Nos animais que receberam injeção de bevacizumab observamos redução significativa do volume de líquido pleural e da permeabilidade vascular, assim como dos níveis pleurais de VEGF e de IL-8, porém sem diferença na celularidade, nos níveis de DHL, proteínas e TGF1. O grau de aderências pleurais também foi significativamente reduzido em todos os coelhos pré-tratados com bevacizumab, porém sem evidente diferença no escore de inflamação pleural independente do esclerosante utilizado. Observou-se ainda, nos animais que receberam anti-VEGF, diminuição da densidade vascular tanto no grupo talco como no nitrato de prata. Houve redução significativa de espessamento e fibrose pleural e da quantidade de colágeno apenas nos animais que receberam nitrato de prata e tratamento prévio com bevacizumab. Conclusão: Este estudo experimental demonstrou que a administração de bevacizumab intravenoso interfere na fase aguda do processo inflamatório pleural induzido pelo talco ou nitrato de prata, provavelmente através de redução da permeabilidade vascular. Evidenciou-se também que este fármaco inibe a formação de aderências pleurais, reduz a densidade vascular, a produção de colágeno e o espessamento pleural, potencialmente interferindo na efetividade da pleurodese induzida por talco ou nitrato de prata. Estes resultados alertam para uma possível redução de efetividade da pleurodese em pacientes em uso de anticorpos anti-VEGF / Introduction: Chemical pleurodesis is widely used to control recurrent malignant pleural effusion. Vascular endothelial growth factor (VEGF) is produced in response to mesothelial injury by sclerosing intrapleural injection and it is a potent angiogenesis inducer. The monoclonal anti-VEGF bevacizumab inhibits VEGF and has been used in the treatment of cancer to reduce angiogenesis and tumour progression. The effects of VEGF blockage on pleural inflammation and pleurodesis induced by talc and silver nitrate were not completely known. Objective: To describe the effects of monoclonal anti-VEGF bevacizumab in the early and late phase of pleurodesis induced by talc or silver nitrate. Methods: One-hundred and fifty-two rabbits were submitted to intrapleural injection of talc (n = 76) or silver nitrate (n = 76). Half of the animals in each group received intravenous bevacizumab, 30 minutes before the sclerosing agent. In each of the four groups, five animals were sacrificed 1, 2, 3, 4, 7, 14 and 28 days after the intrapleural injection. . A subgroup of twelve animals received intravenous Evans blue one hour prior to sacrifice, to estimate the vascular permeability. The pleural fluid volume was quantified and sent for biochemical, cytological and immunological analysis. Macroscopic pleural adhesions were evaluated using a semiquantitative score. The visceral pleura was submitted to microscopic examination to quantify, by score, inflammation and fibrosis. Anti-factor VII immunostaining was used to evaluate vascular density. Pleural thickness and collagen quantification (sirius red stain was used to identify collagen fibers) were evaluated by an image analysis system. Statistical analysis: Results are expressed as mean and standard error measurement (SEM). Differences between two groups were analyzed using t- test and Mann-Whitney rank sum test and considered statistically significant when p-value was <0.05. Results: Animals pretreated with anti-VEGF antibody developed lower volumes of pleural fluid and presented a significant reduction in pleural permeability, VEGF and IL-8 levels in both groups (talc and silver nitrate). There was no difference in total number of cells, TGF1, LDH and total protein in the pleural fluid. Macroscopic adhesions scores were lower and angiogenesis was reduced after pretreatment with bevacizumab in both groups. No significant difference was found in inflammation scores between the two groups. Pleural fibrosis, thickening and collagen were reduced in animals submitted to pleurodesis only in the group silver nitrate pretreated with bevacizumab. Conclusion: This experimental study shows that the administration of anti-VEGF antibody interferes in the acute phase of acute inflammation induced by silver nitrate and talc by reducing vascular permeability. It also reduces macroscopic adhesions, pleural thickening and interferes with pleural fibrosis, decreasing angiogenesis and collagen production. These findings suggest a potential for pleurodesis failure in patients treated with bevacizumab for cancer

Introdução: A pleurodese química é rotineiramente utilizada para o controle de derrames pleurais recidivantes. O fator de crescimento do endotélio vascular (VEGF) é uma citocina produzida em resposta à inflamação pleural induzida por esclerosantes e possui papel essencial na angiogênese e na fibrose pleural. O anticorpo monoclonal bevacizumab bloqueia a ação do VEGF, sendo utilizado no tratamento de algumas neoplasias malignas com o objetivo de inibir a angiogênese e a progressão tumoral. Os efeitos do bevacizumab sobre o processo inflamatório pleural e sobre a pleurodese induzida por talco e nitrato de prata ainda não foram totalmente descritos. Objetivo: Caracterizar a influência do anticorpo monoclonal anti-VEGF, bevacizumab, nas fases precoce e tardia da pleurodese induzida pelo talco ou nitrato de prata. Métodos: Foram estudados 152 coelhos que receberam injeção intrapleural de talco (n=76) ou nitrato de prata (n=76). Metade dos animais em cada grupo recebeu injeção intravenosa de bevacizumab 30 minutos antes do agente esclerosante. Após a injeção intrapleural de talco ou nitrato de prata, 5 animais em cada grupo foram sacrificados em 1, 2, 3, 4, 7, 14 e 28 dias. Um subgrupo de 12 animais recebeu azul de Evans 1 hora antes do sacrifício realizado no terceiro dia, para análise de permeabilidade pleural. Em todos os animais, o líquido pleural obtido foi quantificado, sendo realizadas análises bioquímica, citológica e imunológica. A cavidade pleural foi avaliada macroscopicamente através de escore para quantificação de aderências. Microscopicamente, a pleura visceral foi analisada por escore para o grau de inflamação e fibrose; a densidade vascular foi avaliada por imunohistoquímica (anti fator VIII) e o espessamento pleural e a quantidade de colágeno (fibras colágenas coradas pelo método de picrosirius) mensurados através de um sistema de análise de imagem. Análise Estatística: Os resultados estão expressos em média e erro padrão (SEM). Comparações entre os grupos foram feitas utilizando-se o teste t não-pareado ou Mann-Whitney, sendo considerado significativo um valor de p inferior a 0,05. Resultados: Nos animais que receberam injeção de bevacizumab observamos redução significativa do volume de líquido pleural e da permeabilidade vascular, assim como dos níveis pleurais de VEGF e de IL-8, porém sem diferença na celularidade, nos níveis de DHL, proteínas e TGF1. O grau de aderências pleurais também foi significativamente reduzido em todos os coelhos pré-tratados com bevacizumab, porém sem evidente diferença no escore de inflamação pleural independente do esclerosante utilizado. Observou-se ainda, nos animais que receberam anti-VEGF, diminuição da densidade vascular tanto no grupo talco como no nitrato de prata. Houve redução significativa de espessamento e fibrose pleural e da quantidade de colágeno apenas nos animais que receberam nitrato de prata e tratamento prévio com bevacizumab. Conclusão: Este estudo experimental demonstrou que a administração de bevacizumab intravenoso interfere na fase aguda do processo inflamatório pleural induzido pelo talco ou nitrato de prata, provavelmente através de redução da permeabilidade vascular. Evidenciou-se também que este fármaco inibe a formação de aderências pleurais, reduz a densidade vascular, a produção de colágeno e o espessamento pleural, potencialmente interferindo na efetividade da pleurodese induzida por talco ou nitrato de prata. Estes resultados alertam para uma possível redução de efetividade da pleurodese em pacientes em uso de anticorpos anti-VEGF / Introduction: Chemical pleurodesis is widely used to control recurrent malignant pleural effusion. Vascular endothelial growth factor (VEGF) is produced in response to mesothelial injury by sclerosing intrapleural injection and it is a potent angiogenesis inducer. The monoclonal anti-VEGF bevacizumab inhibits VEGF and has been used in the treatment of cancer to reduce angiogenesis and tumour progression. The effects of VEGF blockage on pleural inflammation and pleurodesis induced by talc and silver nitrate were not completely known. Objective: To describe the effects of monoclonal anti-VEGF bevacizumab in the early and late phase of pleurodesis induced by talc or silver nitrate. Methods: One-hundred and fifty-two rabbits were submitted to intrapleural injection of talc (n = 76) or silver nitrate (n = 76). Half of the animals in each group received intravenous bevacizumab, 30 minutes before the sclerosing agent. In each of the four groups, five animals were sacrificed 1, 2, 3, 4, 7, 14 and 28 days after the intrapleural injection. . A subgroup of twelve animals received intravenous Evans blue one hour prior to sacrifice, to estimate the vascular permeability. The pleural fluid volume was quantified and sent for biochemical, cytological and immunological analysis. Macroscopic pleural adhesions were evaluated using a semiquantitative score. The visceral pleura was submitted to microscopic examination to quantify, by score, inflammation and fibrosis. Anti-factor VII immunostaining was used to evaluate vascular density. Pleural thickness and collagen quantification (sirius red stain was used to identify collagen fibers) were evaluated by an image analysis system. Statistical analysis: Results are expressed as mean and standard error measurement (SEM). Differences between two groups were analyzed using t- test and Mann-Whitney rank sum test and considered statistically significant when p-value was <0.05. Results: Animals pretreated with anti-VEGF antibody developed lower volumes of pleural fluid and presented a significant reduction in pleural permeability, VEGF and IL-8 levels in both groups (talc and silver nitrate). There was no difference in total number of cells, TGF1, LDH and total protein in the pleural fluid. Macroscopic adhesions scores were lower and angiogenesis was reduced after pretreatment with bevacizumab in both groups. No significant difference was found in inflammation scores between the two groups. Pleural fibrosis, thickening and collagen were reduced in animals submitted to pleurodesis only in the group silver nitrate pretreated with bevacizumab. Conclusion: This experimental study shows that the administration of anti-VEGF antibody interferes in the acute phase of acute inflammation induced by silver nitrate and talc by reducing vascular permeability. It also reduces macroscopic adhesions, pleural thickening and interferes with pleural fibrosis, decreasing angiogenesis and collagen production. These findings suggest a potential for pleurodesis failure in patients treated with bevacizumab for cancer