Orientadores: Joyce Maria Annichino-Bizacchi, Nelci Fenalti Hoher / Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-15T09:49:31Z (GMT). No. of bitstreams: 1 Pazzini_Carla_M.pdf: 2143259 bytes, checksum: b3ff6eb2527b691a4021526983ef2aeb (MD5) Previous issue date: 2010 / Resumo: A heparina é um anticoagulante amplamente empregado no tratamento e profilaxia da trombose venosa profunda (TVP). Algumas limitações do seu uso são o custo e a via de administração, endovenosa ou subcutânea, às vezes em doses repetidas em 24 horas. Assim, o desenvolvimento de um produto que possa ser administrado por via subcutânea em um menor número de aplicações ou por via oral, torna-se um importante desafio, e de grande aplicabilidade clínica. A utilização de um sistema de liberação sustentada de fármacos pode vir ao encontro desse objetivo, pois permite que o agente seja protegido e liberado gradativamente. Este projeto consistiu na preparação e caracterização de nanopartículas biodegradáveis de poli (e-caprolactona) (PCL) como carreador de heparina de baixo peso molecular, e avaliação de sua atividade anticoagulante e antitrombótica in vivo. As nanopartículas foram preparadas pelo método de dupla emulsão a/o/a e evaporação de solvente. A caracterização das nanopartículas foi realizada por microscopia eletrônica de varredura (MEV), observando-se nanopartículas esféricas e homogêneas. O diâmetro médio das nanopartículas foi de 269 ± 36 nm e o potencial zeta foi de -1,20 ± 1,93 mV, indicando que as mesmas apresentam carga negativa. A eficiência de encapsulação, analisada pelo método Azure II, foi de 80 ± 2,3%. A liberação da heparina in vitro, avaliada pelo método de Azure II, no período de 24 horas foi de 4 ± 1,8%. Após a adição da esterase houve um aumento para 10 ± 1,9% na liberação de heparina, provavelmente pela aceleração da degradação das partículas pela enzima. A liberação in vivo da heparina encapsulada, após aplicação subcutânea em ratos, foi avaliada pela atividade anti-Xa plasmática através do método colorimétrico, e os resultados foram comparados aos obtidos com heparina livre. A dose de heparina encapsulada teve que ser 5 vezes maior que a dose de heparina livre. A heparina encapsulada em nanopartículas apresentou uma liberação sustentada por até 12 horas, por um período significativamente mais prolongado (P<0,01), mas com menor atividade anti-Xa. Esses dados sugerem que as nanopartículas podem permitir que a heparina seja liberada de uma forma mais gradual, e mesmo em dose mais elevada, não parece estar associada a um risco de atividade acima da faixa terapêutica. Quando se comparou a atividade anti-Xa obtida pela injeção subcutânea de nanopartículas com heparina em doses diversas, 800 UI/Kg e 1000 UI/Kg, ficou demonstrado que o efeito e o tempo de ação dependem da dose aplicada. Para avaliação da ação antitrombótica foi padronizado o modelo de TVP por estase em ratos. As doses de nanopartículas empregadas para a avaliação da ação antitrombótica foram calculadas pela atividade anti-Xa semelhante à obtida com a heparina livre, de 0,3 a 0,7 UI/mL. A heparina livre ou encapsulada em nanopartículas foi aplicada em uma única dose, por via subcutânea. Os resultados mostraram que houve diminuição significativa do trombo formado com a utilização de heparina livre, em comparação ao grupo controle (P=0,004). Praticamente não houve a formação de trombose venosa em nenhum dos ratos que receberam a heparina encapsulada em nanopartículas, com uma diferença significativa tanto em relação ao grupo controle (P<0,001) como ao grupo com heparina livre (P<0,001). Em resumo, o método de dupla emulsão a/o/a mostrou-se um método eficiente para o encapsulamento de heparina, proporcionando a obtenção de nanopartículas esféricas e com alta eficiência de encapsulação. Pelos estudos in vivo, a heparina encapsulada não liofilizada mostrou uma liberação sustentada, por um período superior ao obtido com a heparina livre, e com excelente ação antitrombótica. Caso esses resultados se confirmem através da continuidade deste estudo, a utilização de heparina encapsulada em nanopartículas na prática clínica poderá ser uma realidade com grandes vantagens para o paciente. / Abstract: Heparin is an anticoagulant widely used in the treatment and prophylaxis of deep vein thrombosis (DVT). Some limitations of its use is the cost and route of administration, intravenous or subcutaneous, sometimes in repeated doses in 24 hours. Thus, the development of a product that can be administered subcutaneously in a smaller number of applications or orally becomes a major challenge, with interesting clinical applications. The use of a system for sustained release of drugs can come to meeting that goal, because it allows the agent to be protected and released gradually. This project consisted of the preparation and characterization of biodegradable nanoparticles of poly (e-caprolactone) (PCL) as a carrier of heparin of low molecular weight, and its evaluation of anticoagulant and antithrombotic activity in vivo. The nanoparticles were prepared by the method of double emulsion w/o/w and evaporation of solvent. The characterization of nanoparticles was performed by scanning electron microscopy (SEM), which showed homogeneous spherical nanoparticles. The average diameter of nanoparticles was 269±36 nm and zeta potential was -1.20±1.93 mV, indicating negative charge. The encapsulation efficiency, assayed by Azure II, was 80±2.3%. The release of heparin in vitro, at the 24-hour period was 4±1.8%. After the addition of esterase the release of heparin was increased to 10±1.9%, probably by accelerating the degradation of particles by the enzyme. The in vivo release of encapsulated heparin after subcutaneous administration in rats, was assessed by anti-Xa plasma activity and the results were compared with free heparin. The dose of heparin encapsulated had to be 5 times the dose of heparin free. Heparin-encapsulated nanoparticles showed a sustained release for up to 12 hours for a period significantly longer (P<0.01), but with lower anti-Xa activity. These data suggest that nanoparticles may allow heparin to be released in a more gradual, but with lower activity. When comparing the anti-Xa activity obtained by subcutaneous injection of nanoparticles with different doses of heparin, 800 IU/kg and 1000 IU/kg, demonstrated that the effect and duration of action depends on the dose applied. To evaluate the antithrombotic action of nanoparticles with heparin a model of DVT by stasis in rats was used. The doses of nanoparticles used for the evaluation of antithrombotic action were calculated by anti-Xa activity similar to that obtained with free heparin, 0.3 to 0.7 IU/mL. Heparin free or encapsulated in nanoparticles was applied in a single dose subcutaneously. The results showed a significant decrease of thrombus formed with the use of free heparin, compared with the control group (P=0.004). There were virtually no formation of venous thrombosis in any of the rats that received heparin encapsulated in nanoparticles, with a significant difference both in the control group (P<0.001) and the group with free heparin (P<0.001). In summary, the method of double emulsion w/o/w proved an efficient method for the encapsulation of heparin, providing spherical homogeneous nanoparticles with high encapsulation efficiency. For in vivo studies, heparin encapsulated showed a sustained release for a period greater than that of free heparin, and with excellent antithrombotic action. If these results are confirmed by the continuity of this study, the use of heparin encapsulated in nanoparticles in clinical practice can be of great benefits for the patient. / Mestrado / Medicina Experimental / Mestre em Fisiopatologia Médica

nÃo hà / As doenÃas trombÃticas constituem um sÃrio problema na saÃde mundial. Diversas desordens hereditÃrias, que afetam o sistema fisiolÃgico anticoagulante, estÃo atualmente estabelecidas como fatores de risco para a ocorrÃncia do evento trombÃtico. Dentre estes o fator V Leiden à o mais freqÃente. A associaÃÃo entre alteraÃÃes no gene do fator V e a ocorrÃncia de eventos trombÃticos desencadeou o desenvolvimento de diversas pesquisas. Neste estudo, 100 pacientes portadores de eventos trombÃticos, atendidos no ambulatÃrio de Hematologia do Centro de Hematologia e Hemoterapia do Cearà - HEMOCE/SESA/UFC, foram analisados para a detecÃÃo da presenÃa do fator V Leiden. O grupo controle consistiu de 110 voluntÃrios sadios. A freqÃÃncia encontrada na populaÃÃo controle foi de 2,7% (03/110), enquanto que nos pacientes trombofÃlicos foi de 9% (09/100). Destes, 77,8% (07/09) eram do sexo feminino e 22,2% (02/09) do sexo masculino e a cor predominante foi a parda [66,7% (06/09)]. A faixa etÃria mais freqÃente foi entre 26 e 33 anos [33,4% (03/09)]. Do total dos pacientes portadores do fator V Leiden, 88,9% (08/09) apresentaram trombose venosa profunda e 11,1% (01/09) trombose arterial com recorrÃncia do evento trombÃtico de 22,2% (02/09). A correlaÃÃo entre a presenÃa do evento trombÃtico/presenÃa do fator V Leiden e o uso de contraceptivo oral foi de 71,4% (05/07). Das pacientes portadoras e que usaram contraceptivo oral nÃo ocorreu o aborto. A localizaÃÃo do primeiro evento trombÃtico, nos portadores, foi predominantemente nos membros inferiores [88,9% (08/09)] e 11,1% (01/09), nas artÃrias coronÃrias. Em 44,4% (04/09) havia um ou mais fatores de risco/morbidade associado. A freqÃÃncia da mutaÃÃo encontrada no estado do Cearà mostrou-se inferior aos dados obtidos na regiÃo de Botucatu (SP) - 12% e ao estudo de Benson, em Atlanta (EUA)- 12,4 e ainda menor que os encontrados na regiÃo de Campinas (SP)- 20% e à populaÃÃo com ancestral europeu-18%. A diferenÃa entre pacientes trombofÃlicos e populaÃÃo controle nÃo foi estatisticamente significante (p=0,19), mas o risco estimado para o evento trombÃtico foi de 2,46.

Introdução: A evolução clínica da trombose venosa cerebral (TVC) pode variar desde a recuperação completa ao óbito. Séries européias e um estudo multicêntrico identificaram alguns fatores indicativos de prognóstico da TVC, dado importante na decisão da melhor terapêutica para os pacientes. Este estudo busca identificar, a partir do seguimento prospectivo de cento e onze pacientes com TVC, os fatores prognósticos envolvidos na evolução clínica durante o período de 2 anos. Pacientes Métodos: Foram acompanhados prospectivamente 111 pacientes com diagnóstico de TVC desde a fase aguda do diagnóstico, confirmado por meio de RM de encéfalo e/ou angiografia cerebral (ARM, ATC ou angiografia digital). Obtidos dados do quadro clínico e seguimento por um protocolo clínico. 96% dos pacientes foram anticoagulados na fase aguda com heparina e seguida de anticoagulação com warfarina. Submetidos a investigação para os fatores predisponentes para TVC. A evolução clínica foi quantificada por meio da escala modificada de Rankin (EMR) após 3, 6, 12 e 24 meses, definindo os pacientes de bom prognóstico EMR 1, e mau prognóstico EMR 2. Comparamos dados clínicos da fase aguda e resultados encontrados nos exames de imagem e laboratoriais como possíveis fatores prognósticos, através da análise univariada pelo teste 2 e os fatores de significância estatística (p<0,1), foram analisados com regressão logística ajustada e cálculo da razão de chances (RC), (intervalo de confiança IC=95%). Resultados: A média da idade dos pacientes foi de 35 anos, 72% mulheres, 40% afro-brasileiros. As principais manifestações clínicas foram: cefaléia 97%, déficit focal 47%, crise epiléptica 40%, alteração da consciência 28%, síndrome de HIC (SHIC) isolada 40%. Quanto aos fatores predisponentes; 75% das mulheres usavam anticoncepcional, 31% dos pacientes apresentavam trombofilia hereditária, 13% SAAF, 6% eram portadores de vasculites, 25% outros estados pro trombóticos, 7 % apresentavam fatores locais (infecciosos ou MAV); e 5% das mulheres estavam no puerpério ou gestação. Os dados de neuroimagem revelaram que 42% apresentaram trombose em mais de um sistema venoso, 33% tiveram infartos hemorrágicos e 18% infartos venosos isquêmicos, e 20% dos pacientes apresentaram trombose de veias e seios profundos. Após 24 meses 18 pacientes (17%) apresentaram EMR 2 e os fatores determinantes de pior prognóstico foram: a etnia afro-brasileira p=0,001; RC= 11,37 (95% IC 2.81- 46,08), alteração do nível de consciência p=0,007; RC=4.56 (95% IC 1.61-19.45), sexo masculino p=0,049 RC=3.55 (95% IC 1.00-12.55) e idade acima de 32 anos p=0,05 RC = 3.95 (95% IC 0,97-15.20). A presença isolada de ACO como fator predisponente está associado ao melhor prognóstico p = 0,016; RC=5,17(95% IC 1.37-19.57) e após 24 meses a mortalidade foi de 4,5%. Conclusão: A análise deste trabalho evidencia que a maioria dos pacientes portadores de TVC (83%) apresenta uma evolução benigna com o tratamento, estando após 24 meses assintomáticos ou com sintomas mínimos, e a presença de ACO como fator predisponente isolado a TVC está relacionado ao melhor prognóstico. Os pacientes com pior evolução clínica têm a raça afro-brasileira, a alteração do nível de consciência, sexo masculino e idade acima de 32 anos como fatores determinantes de pior prognóstico em vinte e quatro meses. A identificação destes fatores é importante por direcionar um melhor tratamento na fase aguda da TVC para casos selecionados / Introduction: The cerebral venous thrombosis (CVT) clinical evolution is quite variable from complete recovery to death. Some European series and a multicenter study had identified prognostic factors related to CVT prognosis. The identification of these factors is important for the best therapeutic decision to patients. This study aims to identify the prognostic factors enrolled in clinical evolution of 111 patients with CVT in a prospective outcome clinical trial during two years. Subjects and Methods: One hundred and eleven patients were prospective followed with the diagnosis of CVT since acute phase diagnosis, confirmed by brain MRI and/or brain angiography (MRA , CTA or digital angiography). Information about clinical features and follow-up were filled on a clinical form. 96% of the patients were anticoagulated on heparin followed by warfarin treatment. The patients were investigated to predisposing factors to CVT. The clinical evaluation was accessed by the modified Rakin scale (mRs) after 3, 6, 12 and 24 months, considering patients with good outcome when mRs 2. The acute phase clinical features, laboratory and imaging data were compared as possible prognosis factors beyond univariate 2 test and the factors with statistical significance (p<0,1) and then analyzed by logistic regression adjusted and Odds Ratio values (confidence interval CI=95%). Results: The mean age of the patients was 35 years, 72% were women, and 40% were African Brazilian. The main clinical features observed were: headache 97%, focal sign 47%, epileptic seizure 40%, isolated ICH syndrome 40% and altered mental status 28%. All the patients were investigated to predisposing factors; 75% of the women were on oral contraceptive, 31% of the patients presented hereditary thrombophilia, 13 % antiphospholipid syndrome, 6% presented vasculitis, 25% other protrhrombotic state, 7% presented some local feature (arterialvenous malformation or infection) and 5% of women were pregnant or on puerperium. The neuroimaging data showed that 42% of the patients presented thrombosis in more than one venous system, 33% had hemorrhage infarcts, 18% ischemic venous infarcts and 20% of the patients had thrombosis of the deep venous system. After two years 17% had a mRs > 2 and the features enrolled on poor prognosis were: African Brazilian patients p=0,001; OR= 11,37 (95% IC 2.81- 46,08), altered mental status p=0,007; OR=4.56 (95% IC 1.61-19.45), male gender p=0,049 OR=3.55 (95% IC 1.00-12.55) and age over 32 years p=0,05 OR = 3.95 (95% IC 0,97- 15.20). The presence of oral contraceptives as isolated predisposing factor was related to good outcome CVT p=0,016; OR=5,17(95% IC 1.37-19.57) and after two years the mortality rate was 4,5%. Conclusion: This study data show that most patients with the diagnosis of CVT (83%) has a good outcome with the treatment, after two years follow up they have no symptoms or minimal deficits, and the presence of oral contraceptives as isolated predisposing factor was related to better outcome CVT. The patients with poor prognosis have the African Brazilian ethnic group, altered mental status, male gender and age over 32 years as the factors enrolled on bad clinical evolution in two years. The identification of these factors can have future value on treatment better choice on acute phase to selected CVT patients

Orientador: Joyce Maria Annichino-Bizzacchi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T22:14:32Z (GMT). No. of bitstreams: 1 Prado_LucasBessa_M.pdf: 3008068 bytes, checksum: 3758f8a952dfe1f77c113246b8e2a0bd (MD5) Previous issue date: 2013 / Resumo: A Trombose Venosa Profunda (TVP) é definida como uma oclusão parcial ou total da circulação venosa profunda. A heparina é um fármaco com ação anticoagulante e antitrombótica utilizado desde 1930. O custo, a via de administração (endovenosa ou subcutânea) e as doses repetidas são algumas das limitações do seu uso. Assim, o desenvolvimento de um produto que possa ser administrado por via subcutânea ou oral em um menor número de aplicações, torna-se um importante desafio e de grande aplicabilidade clínica. Sistemas de liberação sustentada permitem que o fármaco seja encapsulado e liberado gradativamente. Este estudo constituiu na preparação, caracterização e avaliação in vivo de nanopartículas de poli (?-caprolactona) (PCL) e quitosana como carreadores de heparina de baixo peso molecular (enoxaparina). As nanopartículas foram preparadas pelo método de dupla emulsão água/óleo/água e evaporação do solvente. A caracterização das nanopartículas foi realizada por microscopia eletrônica de varredura (MEV), onde foram observadas partículas esféricas e homogêneas. O diâmetro médio das nanopartículas foi de 512,8 ± 13,8 nm e o potencial zeta foi de +30,9 ± 1,3 mV. A eficiência de encapsulamento, analisada pelo método Azure II foi de 99,04 ± 0,001 %. A atividade anticoagulante in vivo da enoxaparina encapsulada foi avaliada pela atividade anti-Xa plasmática, através de método colorimétrico. Quando a enoxaparina livre foi administrada por via subcutânea observou-se um pico de atividade (0,5 UI/mL) em 1 hora, com um decréscimo gradual até 6 horas. A atividade anticoagulante da enoxaparina encapsulada em nanopartículas manteve-se por até 14 horas, quando foi administrada por via subcutânea, sugerindo que as nanopartículas podem permitir que a enoxaparina seja liberada de forma gradual, podendo ser uma vantagem na prática clínica. Após a administração das nanopartículas por via oral não se observou nenhuma atividade em até 14 horas, sugerindo que as nanopartículas não tenham sido absorvidas ou a enoxaparina tenha sido degradada no trato gastrointestinal. Para avaliação do efeito antitrombótico foi padronizado o modelo de TVP por estase e hipercoagulabilidade em ratos. Após administração subcutânea, houve uma significativa diminuição do tamanho do trombo formado tanto com o emprego de enoxaparina livre (p= 0,002) como após encapsulamento em nanopartículas (p= 0,0411) em comparação ao grupo controle. Quando foram administradas nanopartículas por via oral, os resultados mostraram que não houve diferença estatística em comparação ao grupo controle (p= 0,9476) e a um grupo de nanopartículas vazias (p= 0,9372). Em resumo, o método de dupla emulsão a/o/a mostrou-se eficiente para o encapsulamento de enoxaparina, proporcionando a obtenção de nanopartículas esféricas e com alta eficiência de encapsulamento. Pelos estudos in vivo, a enoxaparina encapsulada mostrou uma atividade anticoagulante com liberação sustentada, por um período superior ao obtido com a enoxaparina livre, com excelente efeito antitrombótico quando administrada por via subcutânea. Contudo, não se observou nenhum efeito anticoagulante ou antitrombótico quando as nanopartículas foram administradas por via oral. Novos experimentos com quitosanas de diferentes massas molares serão necessários na tentativa de possibilitar a absorção oral dessas nanopartículas / Abstract: Deep vein thrombosis (DVT) is defined as partial or total occlusion of the deep venous circulation. Heparin is a drug with anticoagulant and antithrombotic action used since 1930. The costs, administration vias (intravenous or subcutaneous) and the repeated doses are some limitations of its use. Thus, the development of a product that could be administered subcutaneous or orally in a smaller number of applications becomes a major challenge with huge clinical applicability. Sustained release systems allow the medication to be gradually encapsulated and released. This study was based on the preparation, characterization and in vivo evaluation of nanoparticles of poly (?-caprolactone) (PCL) and chitosan as carriers of low molecular weight heparin (enoxaparin). The nanoparticles were prepared by the double emulsion water/oil/water method and solvent evaporation. The nanoparticles characterization was performed by scanning electron microscopy (SEM), in which were observed spherical and homogeneous particles. The average diameter of the nanoparticles was 512.8 ± 13.8 nm and the zeta potential was +30.9 ± 1.3 mV. The encapsulation efficiency, analyzed by Azure II method, was 99.04 ± 0.001%. The in vivo anticoagulant activity of the encapsulated enoxaparin was evaluated by plasmatic anti-Xa activity performed by colorimetric method. When the free enoxaparin was subcutaneously administered a peak of activity was observed (0.5 IU/mL) in 1 hour with a gradual decrease until 6 hours. The anticoagulant activity of the nanoparticles encapsulated enoxaparin was kept until 14 hours when it was administered subcutaneously, suggesting that nanoparticles may allow the enoxaparin release by a gradual way, what could be an advantage on clinical practice. After the oral administration of the nanoparticles, any activity could be observed in until 14 hours, suggesting that or the nanoparticles might be not absorbed or the enoxaparin might be degraded on the gastrointestinal tract. In order to evaluate its antithrombotic effect, it was standardized a model of DVT by stasis and hypercoagulability in rats. After subcutaneous administration, there was a significative reduction on the thrombus size both with free enoxaparin (p= 0.002) and after encapsulation (p= 0.0411) in comparison with control group. When nanoparticles were administered orally, the results showed no statistical difference compared to the control group (p = 0.9476) and to a group of empty nanoparticles (p = 0.9372). In summary, the double emulsion method w/o/w was efficient for the enoxaparin encapsulation, providing the obtainment of spherical nanoparticles with high encapsulation efficiency. For in vivo studies, the encapsulated enoxaparin showed a sustained release anticoagulant activity for a higher period than that obtained with free enoxaparin, with an excellent antithrombotic effect when administered subcutaneously. However, there was no anticoagulant or antithrombotic effect when the nanoparticles were administered orally. Further experiments with chitosans of different molecular weights will be needed on the attempt to allow the oral absorption of these nanoparticles / Mestrado / Medicina Experimental / Mestre em Fisiopatologia Médica

An infarct is an area which has lost its blood supply due to obstruction, thrombosis or embolism. It is the third leading cause of death in the Western world, following non-cerebral cardiovascular disease and cancer. This research study focused on determining the infarct prevalence according to age, sex and brain areas most affected by infarcts. The prevalence of different infarct types was also determined. Brain MRI statistics were obtained from a Private Radiology practice in Pretoria for a 13-month period. A total of 1844 brain MRI examinations were evaluated, of which 299 patients presented with infarcts. Their age and sex were noted and their individual reports were obtained to record the anatomical structures and brain lobes that were infarcted. The infarct types were also noted. Diffusion-weighted images were used to measure new infarcts, while FLAIR images were used to measure old infarcts. Results showed an overall incidence of 16.10% and vascular structures accounted for 26.63% of these. Most infarcts were new (56.80%) and mainly affected patients aged 70–79 years (31.36%). Normal cerebral infarcts (72.49%) and embolic infarcts (14.50%) were the most common. The parietal lobe (34.91%) and right middle cerebral artery (11.54%) presented with the most infarcts. The right hemisphere (34.91%) presented with slight infarct predominance, but this was not significant when compared to the left (31.95%) hemisphere (Chi square p>0.05). No significant difference was found concerning the overall male to female ratio (Chi square p>0.05). Females aged 18–39 years of age presented with three times more infarcts than their male counterparts. This may possibly be due to their use of oral contraceptives and pregnancy, which increases the risk of thrombosis and embolism. Females over 80 years also presented with higher infarct prevalence, which is expected, since men die at earlier ages due to other co-morbidities such as cancer. / Dissertation (MSc)--University of Pretoria, 2009. / Anatomy / MSc / Unrestricted

Neutrophil extracellular traps (NETs), chromatin released by activated neutrophils, were first described for their antimicrobial properties. NETs have a backbone of DNA and histones lined with microbicidal proteins such as neutrophil elastase. NET release has pathological consequences, particularly within blood vessels where NETs can trap red blood cells and platelets, thus contributing to thrombosis (Chapter 1-Overview). NET formation (NETosis) is an active and coordinated biological process involving many enzymatic components. One enzyme in particular, peptidylarginine deiminase 4 (PAD4), citrullinates histones and is required for chromatin decondensation during NETosis. Neutrophils from PAD4-deficient mice are unable to form NETs. We obtained these mice from our collaborator Dr. Yanming Wang, and thus were able to compare PAD4-/- mice to wild-type (WT) mice in mouse models where NETs are formed. These studies have allowed for investigation of the biological relevance of PAD4 and NETs in vivo in thrombotic and/or inflammatory disease. This dissertation focuses on mouse models of deep vein thrombosis and of sepsis. In venous stenosis, thrombosis is initiated by restricting blood flow in the inferior vena cava (IVC). Here, PAD4-/- mice were greatly protected from thrombus formation (Chapter 2). Leukocyte rolling and platelet plug formation in response to vessel injury were unaffected, indicating that endothelial and platelet activation occurred normally in these mice. The mice did not exhibit any defects in hemostasis, and could be induced to produce deep vein thrombi by infusion of WT neutrophils that formed NETs as a part of the thrombus scaffold. Because there is potential to develop anti-NET therapies in thrombosis, I investigated if NET-deficiency would render mice immunocompromised (Chapter 3). PAD4-/- mice had similar mortality in the cecal ligation puncture model, and they were protected from shock in an LPS sepsis model where NETs are released in the absence of live bacteria. Therapies aimed at NET prevention or destruction would likely be beneficial without compromising host immunity. Thus, in summary, studying PAD4-deficient mice has revealed the impact of NETs in thrombotic/inflammatory disease and identified PAD4 as an attractive therapeutic target.

Dans le cancer, l'activation de la cascade de coagulation et des plaquettes participent à la formation de thromboses, à la croissance tumorale, et les métastases. Ces thromboses représentent une complication clinique chez les patients atteints du cancer du pancréas. Cet état serait dû à expression par la tumeur et leurs microparticules (MPs) de facteur tissulaire (FT). Dans une première partie, nous avons identifié le FT et le FT pathway inhibitor exprimés par les MPs cancéreuses et la P-sélectine plaquettaire impliqués dans la progression tumorale, les métastases et la thrombose associée au cancer du pancréas .Nous avons montré le rôle des intégrines αvβ3 et αvβ et des "neutrophils extracellular traps" dans l’interaction des MPs cancéreuses avec les plaquettes dans des modèles murins de « deep vein thrombosis » et de blessure au laser. Nous avons alors évalué l’efficacité du clopidogrel qui présente une action anti tumorale et thrombotique. Cette étude a permis d’initier une étude clinique de phase III pour d’évaluer le potentiel thérapeutique du clopidogrel chez des patients atteints de cancer du pancréas. Dans une seconde partie, nous avons montré que des neutrophiles exprimant le FT agissent comme « starter » de la formation de thrombi. A l’inverse, dans un modèle d’inflammation stérile, nos travaux montrent le rôle de la P-sélectine plaquettaire dans le slow rolling, l’adhésion et la transmigration des neutrophiles a des temps précoses. L’ensemble de nos résultats suggère que les coopérations cellulaires entre l’endothélium, les plaquettes, les MPs et les neutrophiles constituent des mécanismes essentiels à la thrombose et l'inflammation. / In cancers, the blood coagulation cascade and platelets can be activated to form thrombosis. This state will mainly due by the tumor and their microparticles (MPs) expression of tissue factor (TF), key protein of the coagulation cascade. In the first part of this study, we demonstrated that TF and the TF pathway inhibitor expressed by cancer MPs and the platelet P-selectin are involved in tumor progression, metastasis and the associated thrombosis in pancreatic cancer in mice. We showed the key role-play by αvβ3 and αvβ1 integrins and neutrophils extracellular traps in the interaction between cancer cells-derived MPs and platelets. We also evaluated the effect of clopidogrel, but not aspirin, treatment exhibits an anti-tumor action and limits thrombosis formation in preclinical models of pancreatic cancer. This study initiates a national investigation of a multicenter clinical phase III study to evaluate the therapeutic potential of clopidogrel in pancreatic cancer patients. In the second part of this study, we identified a “population of neutrophils expressing TF” that acts like a starter of the thrombus formation. At the reverse, in a sterile inflammatory model, our work showed the primordial role of platelet P-selectin in the slow rolling, the adhesion and the transmigration of neutrophils. All together our results suggest that the cooperation between the endothelium, platelets, MPs and neutrophils constitute essential mechanisms acting in the thrombosis and the inflammation.

This thesis describes the successful development and initial evaluation of a proof-of-concept wireless monitoring system for improving the effectiveness and safety of pneumatic compression therapy to help prevent deep vein thrombosis (DVT). In the development, an important objective was to make feasible the practical and commercial deployment of such improved therapy systems in future, by focusing on a cost-effective design and implementation. Over the years, pneumatic compression has been shown to be an effective solution for the prevention of DVT. However, different problems and complications related to the use of commercial pneumatic compression de-vices that typically include automatic pressure controllers and pneumatic compression sleeves have been reported. For example, one study reported a high percentage of improperly applied or nonfunctional pneumatic compression devices in routine usage. Technical problems, non-compliance, and human error were identified as the causes behind the failed therapies. Also, it was reported that dedicated in-service instruction did not improve the proper use of the pneumatic compression controllers and sleeves. In another study, significant unanticipated variations between expected and delivered pneumatic compression therapy were reported: expected therapy delivered only an average of 77.8% of the time during the therapy, and much of the time key values related to the outcome of the therapy were found to have variations great than 10%. Specific hazards have also been reported. For example, one patient developed acute compartment syndrome after wearing a pair of pneumatic compression sleeves with faulty pressure release valves. In another case, epidural analgesia masked a malfunction resulting from a reversed connection between four-way plastic tubing of the sleeves and the controller, exposing a patient to a hazardous pressure of around 300mmHg,blocking all blood flow for a prolonged period of time. Newer models of pneumatic compression sleeves and controllers from various manufacturers claim to improve therapy by, for example, increasing the peak blood flow velocity. However, there is no evidence in the published literature to support such claims. A published review of the literature from1970-2002 reached the conclusion that the most important factors in im-proving therapy with pneumatic compression devices, particularly during and after surgery, were the degree of conformance of delivered therapy to the prescribed therapy, patient compliance, and the appropriateness of the site of compression. The inability to monitor delivered therapy and patient compliance remains a problem in efforts to improve pneumatic compression therapy. The above-described problems were addressed in the successful development of the innovative prototype described in this thesis. This wireless monitoring system should improve the effectiveness and safety of pneumatic compression therapy. Also, innovative aspects of the system design allow for cost-effective integration into existing commercial controllers and sleeves. For example, an innovative and potentially patentable usage and reprocess indicator was developed for pneumatic compression sleeves to significantly improve their safety and to reduce their cost of use per patient. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

La maladie cancéreuse et la maladie thrombotique sont des problématiques fréquentes et graves rencontrées en pathologie humaine et en santé publique. Elles ont une relation réciproque médiée par des interactions cellulaires et des mécanismes moléculaires complexes faisant intervenir des acteurs de l’hémostase et de l’immunité. Tout ou partie de ces phénomènes rendent en effet compte du processus d’inflammation et de réponse de l’organisme à l’agression. La caractérisation de certains médiateurs moléculaires ayant des rôles connus dans l’hémostase et l’inflammation peut nous permettre d’améliorer la compréhension de ces phénomènes et de proposer des pistes de réflexion diagnostiques ou thérapeutiques.Nous nous sommes donc intéressé au couple facteur Willebrand/ADAMTS13 : une protéine clé de l’hémostase dont le taux est influencé par les processus inflammatoires et sa protéase régulatrice. Cette étude menée chez des patients atteints de cancer nous a permis de montrer que l’utilisation de ces protéines comme des biomarqueurs peut améliorer la stratification du risque individuel de thrombose pour les patients et donc d’améliorer la prise en charge thérapeutique. Le rôle de ces protéines dans la physiopathologie de ces mécanismes reste à préciser.Par ailleurs, sur la base de connaissances structurelles, nous avons l’émis l’hypothèse d’une interaction entre deux récepteurs de la surface des leucocytes, cellules-clés de la réponse inflammatoire. En effet, PSGL-1 (P-sélectine glycoprotéine ligand 1), récepteur présent sur une grande partie des leucocytes est le ligand de la P-sélectine sur l’endothélium vasculaire et joue un rôle majeur dans le roulement des leucocytes permettant leur recrutement aux sites de l’inflammation. PSGL-1 a une structure riche en acides sialiques. Le Siglec-5 est quant à lui un récepteur de structure proche des immunoglobulines qui lie des acides sialiques. Nous avons donc décrit et caractérisé la liaison entre ces deux protéines, et étudié son rôle dans le roulement des leucocytes in vitro et in vivo. Avant d’envisager toute application, il reste bien sûr à caractériser plus précisément les modalités de cette interaction (site de liaison, etc…) et son effet dans d’autres mécanismes régulés par l’interaction PSGL-1/P-sélectine comme la formation du thrombus. / Cancer and thrombosis are frequent and serious concerns in human pathology and public health. This conditions are known to share closed relationships, and reciprocal promotion involving cellular interactions and complex molecular mechanisms. Molecular pathways often involve hemostasis or immunity actors and participate in inflammation process, which can be either cause or consequence. Improved knowledge on molecular mediators at the crossroads of hemostasis and inflammation may allow best understanding of these mechanisms and improving therapeutic management.Thus, we studied Willebrand factor / ADAMTS13 couple : a key protein in hemostasis whose rate is influenced by inflammatory processes and its regulatory protease. This study in cancer patients shows that Willebrand factor and ADAMTS13 could be used as biomarkers to predict individual thrombosis risk and thus improve therapeutic management. Precise role of this proteins in cancer-mediated thrombosis remain unexplored.Furthermore, we hypothesized an interaction between two leukocyte receptors : PSGL-1(P-selectin glycoprotein ligand-1) and Siglec-5. Leukocytes, especially neutrophils are recruited to inflammation sites after a key step of rolling along vasculature. PSGL-1 expressed on the majority of leukocytes is P-selectin ligand and plays a major role in leukocyte rolling. PSGL-1 has a structure rich in sialic acids. Siglec-5 is an immunoglobulin-like receptor and binds sialic acids. Thus, we described and characterized the interaction between these two proteins, and studied its role in leukocyte rolling in vitro and in vivo. Before considering any application, the modalities of this interaction should further analyzed (binding site, etc. ...) and its effect in other mechanism involving PSGL-1/P-selectin interaction like thrombus formation.

A 41‐year‐old man presenting with unstable angina was found to have diffuse coronary ectasia with a partially occluding thrombus in the proximal left anterior descending artery. Anticoagulation with heparin followed by warfarin resulted in relief of angina and resolution of thrombosis at follow‐up angiography 3.5 months later. The patient remains well after three years. Nonatherosclerotic ectatic coronary arteries are prone to thrombosis possibly because of spasm, intimal damage, and blood current eddies. We believe that chronic warfarin therapy may be indicated in many patients with coronary ectasia.