Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [135]-144).

Thesis (Ph.D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed on July 19, 2010). Includes bibliographical references.

P. falciparum est le principal responsable des formes graves du paludisme. Le parasiteévolue entre deux hôtes (homme et moustique) qui lui imposent différents environnements; ettout particulièrement, des modifications des pressions partielles d’O2 nécessitant des capacitésd’adaptation surprenantes pour un parasite microaérophile. Chez l’hôte vertébré, lesphénomènes de cytoadhésion, ralentissant la progression du parasite notamment au niveau despoumons, augmentent la durée d’exposition aux conditions hyperoxiques.La dynamique de la réponse parasitaire à l’hyperoxie a été étudiée par une approchecombinée de transcriptomique et de protéomique. Certains mécanismes de défense contre lesespèces réactives d’oxygène ont été appréciés, dont une éventuelle fonction oxydasealternative.L’exposition du parasite à 21% d’O2 induit un retard de croissance au niveau de laschizogonie. Le stress oxydatif induit par l’hyperoxie entraîne des perturbations métaboliquescomme une inhibition de la glycolyse en faveur de la respiration et un ralentissement dumétabolisme de la vacuole digestive. Cette action combinée sur le métabolisme mitochondrialet vacuolaire permet au parasite de s’adapter à un environnement hyperoxydant, en régulant laproduction d’espèces réactives d’oxygène. Nos travaux ont montré qu’un inhibiteur de lafonction oxydase alternative, l’acide salicylhydroxamique ou SHAM, avec un effet mineur surla croissance parasitaire en microaérophilie, avait un effet létal sur les parasites en hyperoxie.Une meilleure compréhension de la biologie parasitaire pourrait contribuer audéveloppement de nouveaux traitements antipaludiques associés à une thérapie hyperbarique. / P. falciparum is the main species responsible for severe case of malaria. The parasiteevolves between two hosts (human and mosquito), imposing to it different environments;especially changes in the O2 pressure, demanding astonishing adaptation skills for amicroaerophilic parasite. In the vertebrate host, the phenomena of cytoadhesion, which slowdown the spread of the parasite among others in the lungs, increase the timing of exposure tohyperoxic conditions.The parasitic response dynamic to hyperoxia has been analysed by a combinedtranscriptomic and proteomic approach. Some of the defense mechanisms against reactiveoxygen species have been evaluated, among which a potential alternative oxidase function.The exposure of the parasite to 21%O2 atmosphere leads to a growth delay atschizogony level. The oxidative stress resulting from the hyperoxia conducts to metabolicalterations, as an inhibition of the glycolysis in favour of respiration and as a slowdown of themetabolism of the digestive vacuole. This combined action on the mitochondrial and vacuolarmetabolisms allows the parasite to adapt itself to hyperoxic environment, by regulatingreactive oxygen species. Our works have shown that an inhibitor of the alternative oxidasefunction, the salicylhydroxamic acid or SHAM, with a minor effect on the parasite growth inmicroaerophily, had letal effect on parasites in hyperoxia.A better understanding of the parasitic biology could contribute to the development ofnew antimalarial treatments, associated with a hyperbaric oxygen therapy.

Le paludisme, responsable du décès d’un million de personnes chaque année, reste un problème majeur de santé publique. Des études récentes ont évoqué des mécanismes immunopathologiques communs entre les manifestations allergiques et le paludisme, soutenus par l’existence d’un homologue parasitaire du facteur de relargage d’histamine humain (PfTCTP). Notre objectif était de déterminer l’implication des acteurs de la réponse allergique dans la gravité de l’accès palustre, et la capacité de la PfTCTP à moduler ces réponses.Trois groupes de sujets ont été recrutés dans des structures de santé à Dakar. Les patients infectés présentaient des taux élevés d’IgE totales et spécifiques, par rapport aux sujets sains, mais sans corrélation avec la gravité. A l’aide d’un test d’activation des basophiles basé sur l’expression du CD203c, nous avons montré que les basophiles de patients en accès simple présentaient un niveau d’activation basal significativement réduit. Ces mêmes patients présentaient des concentrations plasmatiques élevées en IL-10, suggérant un meilleur contrôle de leur réponse inflammatoire. Les basophiles de patients en accès grave présentaient une hyperréactivité à l’hémozoïne, ainsi qu’à des stimulations IgE-dépendantes (anti-IgE). Enfin, la présence de PfTCTP circulante a été associée à une plus grande réactivité des basophiles, tandis que l’acquisition d’anticorps contre cette protéine est associée à une protection envers une trop grande réactivité cellulaire.En conclusion, nos travaux soutiennent l’hypothèse d’une activation allergique excessive au cours du paludisme grave. Ce travail ouvre la voie à de nouvelles approches thérapeutiques. / Malaria is responsible of the death of a million person each year and remains a major public health problem. Recent studies have suggested the existence of common immunopathologic mechanisms between allergic manifestations and malaria, supported by the existence of a parasite homolog of the human histamine releasing factor (PfTCTP). Our objective was to determine i) the implication of allergic response actors in the severity of malaria, and ii) the ability of PfTCTP to modulate these responses.Three groups of subjects were recruited in health structures in Dakar. Infected patients presented high levels of total and specific IgE, compared to healthy controls, although not correlated with severity. With a basophil activation test based on CD203c expression, we demonstrated that basophils from mild malaria patients presented a significantly reduced basal level of activation which paralleled higher levels of IL-10, thus suggesting a better control of their inflammatory responses. Basophils from severe malaria patients showed an hyperreactivity to haemozoin and to IgE-dependent stimulations (anti-IgE). Finally, presence of circulating PfTCTP was associated with a higher basophil reactivity, whereas acquisition of anti-PfTCTP antibodies was associated with protection towards excessive cellular reactivity.In conclusion, our results support the hypothesis of an excessive allergic activation during severe malaria. This work might open the way to new therapeutic approaches.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2012-07-30T21:16:53Z No. of bitstreams: 1 Matheus Santos de Sá Avaliacao da atividade antimalarica de substancias obtidas de especies vegetais....pdf: 9210254 bytes, checksum: 6b1ee3754729e2a51460a41ce1709423 (MD5) / Made available in DSpace on 2012-07-30T21:16:53Z (GMT). No. of bitstreams: 1 Matheus Santos de Sá Avaliacao da atividade antimalarica de substancias obtidas de especies vegetais....pdf: 9210254 bytes, checksum: 6b1ee3754729e2a51460a41ce1709423 (MD5) Previous issue date: 2011 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil / A malária é uma das mais importantes infecções parasitárias de seres humanos devido à alta morbidade e mortalidade atribuídas a esta doença, que constitui uma ameaça para mais de dois bilhões de pessoas vivendo nas áreas de alta incidência. O Plasmodium falciparum, um dos agentes causadores da malária, apresenta alta capacidade de adaptação por mutação e pode ser resistente a vários tipos de drogas antimaláricas já disponíveis, como a cloroquina, o que torna importante a busca de novos antimaláricos. A região do semi-árido brasileiro abrange cerca de 11,5% do território nacional, e possui o bioma menos estudado em relação à flora e fauna, e um dos que tem sofrido maior degradação pelo uso desordenado e predatório nos últimos 400 anos. Tendo em vista o potencial farmacológico dos produtos naturais, o objetivo desse trabalho foi avaliar a atividade antimalárica de substâncias puras extraídas de espécies vegetais nativas ou endêmicas do semi-árido brasileiro e derivados sintéticos. A partir de uma biblioteca de 160 substâncias triadas para atividade antimalárica, foram selecionadas duas classes de compostos para avaliações in vitro e in vivo: o ácido betulínico e derivados, bem como o lapachol e derivados. Foi selecionada ainda uma terceira classe de moléculas, as fisalinas, utilizando o método do Similarity Ensemble Approach (SEA), que previu a ação antimalárica dessas substâncias. Dentre os derivados do ácido betulínico testados, o acetato do ácido betulínico apresentou a maior potência farmacológica in vitro quando comparado com os outros derivados, e foi ativo in vivo. A atividade antimalárica das fisalinas foi confirmada em ensaios in vitro. Ao serem analisadas in vivo, as fisalinas F e D apresentaram resultados opostos (exacerbação e proteção contra a infecção, respectivamente), possivelmente devido à atividade imunossupressora da fisalina F e ausente na fisalina D. A análise do lapachol e seus derivados iniciou-se através de estudos in silico por Quantitative Structure-Activity Relationship (QSAR), que indicaram ser o isolacet o derivado com maior atividade, o que foi confirmado por ensaios in vitro. A atividade antimalárica do isolacet foi confirmada in vivo, sendo ainda realizados estudos de Docking desta molécula com a falcipaína 2 de P. falciparum, que indicaram ser esta cisteíno-protease um possível alvo do isolacet. Nossos resultados indicam o potencial antimalárico de compostos isolados a partir de plantas do semi-árido e demonstram a importância da associação de várias abordagens para entendimento dos mecanismos de ação de moléculas com atividade farmacológica. / Malaria is one of the most important parasitic infections of humans due to the high morbidity and mortality attributed to this disease, which threatens to over two billion people living in areas with high incidence. Plasmodium falciparum, a causative agent of malaria, has a high capacity to adapt by mutation and may be resistant to various antimalarial drugs already available, such as chloroquine, which makes it important to search for new antimalarials. The Brazilian semi-arid region cover about 11.5% of the country, and the biome has been less studied in relation to flora and fauna, and one who has suffered further degradation and predation by the inordinate use in the last 400 years. Given the pharmacological potential of natural products, the aim of this study was to evaluate the antimalarial activity of pure compounds extracted from native or endemic plant species of arid and semi-synthetic derivatives. From a library of 160 substances screened for antimalarial activity, we selected two classes of compounds for evaluation in vitro and in vivo: The betulinic acid and derivatives, as well as lapachol and derivatives. It was also selected a third class of molecules, physalins using the method of Similarity Ensemble Approach (SEA), who predicted the antimalarial action of these substances. Among the tested derivatives of betulinic acid, betulinic acid acetate showed the highest pharmacological potency in vitro when compared with other derivatives, and was active in vivo. The antimalarial activity of physalins was confirmed in vitro assays. When analyzed in vivo the physalins F and D had the opposite results (exacerbation and protection against infection, respectively), possibly due to the immunosuppressive activity of physalin F and absent in physalin D. The analysis of lapachol and its derivatives was initiated through studies in silico by Quantitative Structure-Activity Relationship (QSAR), which indicated that the isolacet the derivative with greater activity, which was confirmed by in vitro assays. The antimalarial activity of isolacet was confirmed in vivo, and further studies of this molecule by Docking with falcipain 2 P. falciparum, which indicated that this cysteine protease is a possible isolacet target. Our results indicate the potential antimalarial compounds isolated from plants of the semi-arid and demonstrate the importance of the combination of various approaches to understanding the mechanisms of action of molecules with pharmacological activity.

Submitted by Nuzia Santos (nuzia@cpqrr.fiocruz.br) on 2015-11-20T18:09:59Z No. of bitstreams: 2 Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) / Approved for entry into archive by Nuzia Santos (nuzia@cpqrr.fiocruz.br) on 2015-11-20T18:10:13Z (GMT) No. of bitstreams: 2 Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) / Made available in DSpace on 2015-11-20T18:10:13Z (GMT). No. of bitstreams: 2 Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) Nicolli.pdf: 41800532 bytes, checksum: a9af9766127bc87ea21823b743fd530e (MD5) Previous issue date: 2015 / Fundação Oswaldo Cruz. Centro de Pesquisa Rene Rachou. Belo Horizonte, MG, Brasil / A resistência de Plasmodium falciparum aos antimaláricos esquizonticidas sanguíneos disponíveis, como a atovaquona e derivados de artemisinina, e a de P. vivax à cloroquina (CQ), exige a busca por alternativas quimioterápicas, objetivo deste trabalho. Como estratégia geradora de novos protótipos antimaláricos, foram feitas modificações estruturais (i) na CQ, as quais resultaram em 10 análogos de cloroquina (AnCQ), sendo quatro complexados com platina (AnCQPt), com atividade previamente descrita na malária pelo P. berghei; (ii) na atovaquona, originando oito naftoquinonas; e (iii) no lapachol, resultando em 11 compostos naftoquinoidais. Essas classes de moléculas foram avaliadas in vitro quanto a sua citotoxicidade (MCL50) e atividade antiplasmodial (IC50) contra parasitos sensíveis (S) ou resistentes (R) à CQ. Os índices de seletividade (IS), expressos pela razão entre essas duas atividades biológicas, foram obtidos. Os AnCQ foram mais ativos contra P. falciparum CQ-R in vitro e mais ativos que os AnCQPt e mostraram IS superiores ao da CQ. Para elucidar seu modo de ação, os AnCQ foram avaliados in silico quanto à ancoragem molecular na lactatodesidrogenase de P. falciparum (PfLDH) ou humana (HssLDH). O AnCQ33 apresentou melhor conformação na PfLDH; AnCQ37 apresentou especificidade em relação à enzima humana. Os AnCQ com maiores IS (AnCQ 33 e 37) e a CQ foram ainda avaliados quanto sua capacidade de inibir a formação de -hematina, sendo tão ou menos ativos que a CQ. Avaliados quanto ao potencial de causar a morte (atividade citocida) ou impedir o crescimento (atividade citostática) de P. falciparum CQ-S e CQ-R, esses análogos demonstraram potencial citocida similar, e potencial citostático maior contra parasitos CQ-R. Os AnCQ foram ativos contra parasitos CQ-S e CQ-R na malária pelo P. berghei. Duas naftoquinonas (2 e 5) apresentaram IS superiores ao da CQ e inibiram a parasitemia pelo P. berghei em camundongos, com destaque para a naftoquinona 2. Em conclusão, os melhores candidatos à produção de um antimalárico esquizonticida sanguíneo foram AnCQ33 e 37 e a naftoquinona 2. / The resistance of P. falciparum to the available blood-schizonticidal antimalarials, such as atovaquone (ATVQ) and artemisinin derivatives, and that of P. vivax to chloroquine (CQ), requires the search for new chemotherapeutic alternatives, aim of this work. As a strategy of generating new antimalarial prototypes, structural modifications were performed (i) on CQ which provided 10 chloroquine analogs (CQAn), four of which being platinum-complexed (CQAnPt), with activity previously described against P.berghei-malaria; (ii) on atovaquone, providing eight naphthoquinones; and (iii) on lapachol, providing 11 naphthoquinoidal compounds. These classes of molecules were evaluated in vitro for their cytotoxicity (MLD50) and antiplasmodial activity (IC50) against CQ-sensitive (S) or resistant (R) parasites. The selectivity indexes (SI), expressed by the ratio between these two biological activities, were obtained. The CQAn were more active against CQ-R P. falciparum in vitro and more active than the CQAnPt, and exhibited SI higher than that of CQ. To elucidate their mode of action, the CQAn were evaluated in silico for molecular docking to the lactate-dehydrogenase of P. falciparum (PfLDH) or humans (HssLDH). The CQAn33 exhibited the best conformation inside PfLDH; CQAn37 exhibited specificity in relation to the human enzyme. The CQAn having the highest SI were evaluated for their ability to inhibit -haematin formation, being so or less active than CQ. Evaluated for their potential to kill (cytocidal activity) or prevent growth (cytostatic activity) of P. falciparum CQ-R and CQ-S, these analogs demonstrated similar cytocidal potential, and higher cytostatic potential against CQ-R parasites. The CQAn were active against CQ-R and CQ-S parasites in P.berghei-malaria. Two naphthoquinones (2and 5) exhibited SI higher than that of CQ and inhibited P. berghei-parasitemia in mice, with highlight to naphthoquinone 2. In conclusion, the best candidates for the production of a blood-schizonticidal antimalarial were CQAn33, 37 and the naphthoquinone 2

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-02-19T13:19:42Z No. of bitstreams: 1 Clarissa Cunha Santana Avaliação... 2015.pdf: 1937824 bytes, checksum: 1d212794cc3bec0caa6b8414a186531b (MD5) / Approved for entry into archive by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-02-19T13:19:53Z (GMT) No. of bitstreams: 1 Clarissa Cunha Santana Avaliação... 2015.pdf: 1937824 bytes, checksum: 1d212794cc3bec0caa6b8414a186531b (MD5) / Made available in DSpace on 2016-02-19T13:19:53Z (GMT). No. of bitstreams: 1 Clarissa Cunha Santana Avaliação... 2015.pdf: 1937824 bytes, checksum: 1d212794cc3bec0caa6b8414a186531b (MD5) Previous issue date: 2015 / Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / A malária é uma doença causada por cinco espécies de parasitos do gênero Plasmodium que causa anualmente a morte de milhares de pessoas, principalmente em países pobres da África. Muito antiga, uma diversidade de fármacos já foram empregados na tentativa de erradicação da doença, entretanto o aparecimento de cepas resistentes, bem como efeitos adversos gerados pelo tratamento impossibilitou tal ação. Os quinolínicos configuram uma grande parte destes tratamentos, apresentando uma notável atividade antimalárica. Neste trabalho nós avaliamos o potencial antimalárico de três novos derivados quinolínicos BS 260, BS 318 e BS 373 em culturas de Plasmodium falciparum, cepa w2, cloroquina resistente. BS 373 apresentou melhor atividade contra culturas de Plasmodium falciparum e, assim como o BS 318, foi capaz de inibir a biocristalização de hemozoína pelos parasitos. A microscopia eletrônica de transmissão revelou uma desorganização celular, diminuição do tamanho e quantidade de cristais de hemozoína no vacúolo digestivo, bem como vacuolizações citoplasmáticas e presença de estruturas membranares no vacúolo digestivo, o que indica a ocorrência de um processo autofágico nas células tratadas com 10 LM e 20 LM do BS 373. A presença de cristais citoplasmáticos indica a ocorrência de autólise pela ruptura da membrana do vacúolo digestivo. Por fim, o efeito dos tratamentos se mostrou irreversível nos parasitos com 24 horas de tratamento para BS 318 e BS 373, enquanto que para BS 260 essa irreversibilidade só foi observada após 48 horas. Nossos dados mostram que os derivados quinolínicos testados são efetivos contra culturas de P. falciparum, configurando bons candidatos à novas moléculas antimaláricas. / Malaria is a disease caused by five Plasmodium species that cause deaths of thousands of people annually, mostly in poor countries of Africa. Very anccient, a variety of drugs have been used in an attempt to eradicate the disease, however the emergence of resistant strains, as well as adverse effects caused by treatment prevented such action. The quinoline are a large part of these treatments, presenting a remarkable antimalarial activity. In this paper we evaluate the antimalarial potential of three new quinoline derivative BS 260, BS 318 and BS 373 in Plasmodium falciparum chloroquine resistant, w2 strain, cultures. BS 373 showed the best activity against Plasmodium falciparum cultures, while and analogously to BS 318 was able to inhibit the hemozoin formation by parasites. The transmission electron microscopy revealed a cell disorganization, decreased size and amount of hemozoin crystals in the digestive vacuole, cytoplasmic vacuolization and presence of membrane structures in the digestive vacuole, which indicates an autophagic process in cells treated with 10 LM and 20 LM BS 373. Cytoplasmic being crystals indicate parasite cell autolusis caused by digestive vacuole membrane disrupture. Finally, the effect of treatment proved irreversible on parasites at 24 hours of treatment for BS 318 and BS 373, whereas for BS 260 this irreversibility was only observed after 48 hours. Our data show that the quinoline derivatives tested are effective against P. falciparum cultures, setting good candidates for new antimalarial molecules.

A malária é uma doença tropical de grande relevância para a saúde pública no mundo. O objetivo do presente estudo foi construir a curva endêmica das espécies de Plasmodium falciparum e vivax, no período de 2003 a 2012 no Garimpo do Lourenço, verificando o efeito da periodicidade e da sazonalidade. Trata-se de um estudo ecológico, de série temporal e de caráter descritivo e exploratório, cujos dados foram obtidos do SIVEP-Malária, e o número de casos notificados ao mês foi utilizado como a variável dependente. Na amostra desta série 69% dos infectados eram do sexo masculino. As taxas cumulativas de infecção por gênero foram similares, sendo a infecção por P.vivax responsável por 75,4% das infecções em mulheres e por 72% do total de infecção em homens. As taxas por faixa etária foram de 72% entre 15 a 49 anos e de 39,6% em menores de 15 anos. Quanto à escolaridade, 66,57% não estudaram ou tinham menos de quatro anos de escolaridade. Observou-se um total de 12.357 infecções, de 12.056 casos novos e de 301 lâminas de verificação de cura (LVC). A infecção em garimpeiros foi responsável por cerca de 40% dessas infecções. Na avaliação da curva endêmica, realizada por meio do teste Augmented Dickey-Fuller, observou-se a ausência de estacionariedade das duas espécies (p > 0,05). A periodicidade, avaliada pelo teste G de Fisher, não evidenciou diferença estatisticamente significativa para os períodos da infecção no curso do ano para nenhuma das duas espécies (p > 0,05). O contexto observado nas zonas de garimpo da Amazônia Brasileira poderiam ser apoiadas por ações de controle ambiental e pesquisas, direcionados aos mosquitos transmissores, ao comportamento das espécies e aos aspectos climáticos, além do apoio à rede de serviços de saúde, de forma a interromper a cadeia de transmissão e controlar a endemia em patamares reduzidos nessa região garimpeira específica. / Malaria is a tropical disease of great relevance for the world’s public health. The objective of the present study was to construct the endemic curve of the species falciparum and vivax during the period starting from 2003 until 2012 in gold mining of Lourenço, assessing the effect of periodicity and seasonality. The present is an ecological time-series, descriptive and exploratory study, whose data were obtained from the SIVEP-Malária, using the number of cases per month as the dependent variable. 69% of those infected were male. Cumulative rates of infection by gender were similar, where vivax was responsible of 75.4% of the infections in females, and of 72% in males. Rates by age were 72% in those between 15 to 49 years old, and of 39.9% in those younger than 15 years old. Regarding literacy, 66.57% of the sample had never studied or had less than four years of schooling. It was observed a total of 12357 infections, 12056 new cases and 301 cure verification slides (CVS). Infection of gold miners was responsible of around 40% of the cases. Endemic curve assessment was performed using the Augmented Dickey-Fuller test, showing absence of seasonality of the two species (p > 0.05). Periodicity was assessed using the Fisher’s G test that did not show statistically significant difference for the infection periods along the year among the two species (p > 0.05). The context observed in the mining areas of the Brazilian Amazon could be supported by environmental control measures and research, targeted to mosquitoes, the behavior of species and climatic aspects and the support to the network of health services in order to stop the transmission chain and control endemic at low levels that specific gold mining region.

L'artémisinine (ART) est un composé antipaludique majeur très actif sur les souches multi-résistantes de Plasmodium falciparum. Cependant, son application clinique est limitée par sa faible solubilité en milieu aqueux et sa faible biodisponibilité par voie orale. La mise en œuvre de cyclodextrines (CDs) bioestérifiées et de dérivés amphiphiles polyoxyéthylénés permet de viser deux objectifs : i) d'une part d'améliorer la concentration aqueuse d'ART à travers son association aux vecteurs colloïdaux de CDs modifiées et ii) d'autre part d'améliorer sa biodisponibilité et son efficacité thérapeutique à travers la décoration de la surface des vecteurs. La décoration surfacique est sensée augmenter le temps de circulation sanguine des nanovecteurs de manière à maintenir des doses plasmatiques efficaces d'ART sur une longue période, suite à une administration intraveineuse. Des suspensions colloïdales stables suffisamment chargées d'ART ont été mises au point permettant de palier le problème d'insolubilité en milieu aqueux de la molécule active et donc d'envisager son administration par voie parentérale. Les essais de lyodisponibilité indiquent que l'ART est libérée des nanosystèmes pendant une période de 4 jours pour les nanoréservoirs et de 11 jours pour les nanosphères. En plus des caractérisations physico-chimiques et pharmacotechniques, les potentialités des nanoparticules décorées en surface ont été évaluées et comparées au cours de tests biologiques. In vitro, l'ART mise en forme a montré une bonne efficacité sur des souches plasmodiales choloroquino-sensibles (3D7) et chloroquino-résistantes (K1) avec des CI50 très faibles de l'ordre de 3 à 6 ng/mL. Le concept de co-nano-assemblage de dérivés amphiphiles de γ-CD-C10 bioestérifiée et de polyéthylène glycol (PEG) dans les conditions de nanoprécipitation semble être une approche intéressante pour conférer des propriétés de furtivité aux nano-systèmes de γ-CD-C10. En effet, les études in vitro mettent en évidence une diminution significativement de la phagocytose par les cellules macrophagiques et/ou de l'adsorption des protéines du complément sérique à la surface des nanoparticules de γ-CD-C10 décorées par le polysorbate 80, le stéarate de PEG1500, et le DMPE-mPEG2000. In vivo, nous observons une augmentation du temps de circulation sanguine des nanoréservoirs γ-CD-C10/polysorbate 80 et des nanosphères γ-CD-C10/DMPE-mPEG2000. Enfin, les études de pharmacocinétique réalisées chez le rat montrent que les paramètres pharmacocinétiques de l'ART sont améliorés lorsqu'elle est associée aux deux systèmes nanoparticulaires précédents. En effet, des valeurs de clairance plasmatique très faibles et de temps de demi-vie plasmatique longs (3 et 5 heures, respectivement) de l'ART ont été enregistrées avec ces deux formulations. Ces formes vectorisées d'ART mises au point ouvrent de perspectives intéressantes pour la prise en charge thérapeutiques des crises de paludisme sévère. / Artemisinin (ART), an endoperoxide sesquiterpene lactone antimalarial drug isolated from a Chinese medicinal herb (Artemisia annua), has a fast action against chloroquine-sensitive and chloroquine-resistant strains of P. falciparum, making it very effective in the treatment of multidrug-resistant malaria. However, its poor aqueous solubility, short half-life, and high first-pass metabolism limit its use in therapeutics. The purpose of the present study was to investigate the potential of self-assembled bio-transesterified CD-based nanocarriers as ART delivery systems for an intravenous route. The objective of our study was twofold: (i) to improve the ART dosage through its association with CD esters-based nanocarriers, (ii) to ensure a sufficient blood circulation time of the nanocarriers through their surface decoration, which is a prerequisite to reach infected erythrocytes after systemic administration. Stable colloidal suspensions with good ART association rate were developed to solve the problem of insolubility in aqueous medium of the active molecule and therefore consider its parenteral administration. The γ-CD-C 10 based nanospheres showed a significant sustained release profile of ART extended up to 4 days for nanosphères and 11 days for nanoreservoirs. In addition to the physicochemical characterizations, the potential of nanoparticles decorated on the surface were evaluated and compared in biological tests. The results from this study indicate that ART-loaded nanosystems, mainly PEGylated ones exhibit satisfactory in vitro activity against Chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of P. falciparum with very low IC50 of the order of 3 to 6 ng / mL. The concept of co-assembly of nano-amphiphilic derivatives of γ-CD-C10 bioestérifiée and polyethylene glycol (PEG) under conditions of nanoprecipitation seems to be an interesting approach to impart stealth nano-systems-γ-CD C10. Indeed, in vitro studies show a significant decrease in phagocytosis by macrophages and/or adsorption of serum complement proteins on the surface of nanoparticles of γ-CD-C10 decorated by polysorbate 80, PEG1500 stearate, and mPEG2000-DMPE. In vivo, we observed an increase in blood circulation time of nanoreservoirs γ-CD-C10/polysorbate 80 and nanospheres γ-CD-C10/DMPE-mPEG2000. Finally, pharmacokinetic studies in rats show that the pharmacokinetics of ART are enhanced when combined with previous two nanoparticle systems. Indeed, values of plasma clearance and very low time of long plasma half-life (3 to 5 hours, respectively) of ART were recorded with both formulations. These colloidal forms of ART developed open up interesting prospects for the therapeutic treatment of severe malaria.

Resumo: O sistema sangüíneo ABO (sABO) é o mais importante sistema na compatibilidade de grupos sangüíneos. Muitas pesquisas têm mostrado associações deste sistema com várias doenças infecciosas, inclusive a malária. Este estudo avaliou a associação entre os genótipos do sistema histo-sangüíneo ABO e a malária não grave causada pelo Plasmodium falciparum. A genotipagem dos grupos sangüíneos do sistema ABO foi feita de acordo com o protocolo de PCR/ RFLP, em amostras de indivíduos maláricos e não maláricos de áreas da Amazônia brasileira. O genótipo homozigoto ABO*O01O01 foi prevalente tanto nos maláricos quanto nos doadores de sangue. O genótipo ABO*AB representou cerca de 3% da população infectada e 5% da não infectada. Não foram verificadas diferenças estatisticamente significantes na comparação das freqüências alélicas e genotípicas do sABO entre pacientes e grupo controle, mesmo quando foram analisados apenas indivíduos com infecções puras de P. falciparum. A freqüência do sABO na Amazônia brasileira pode estar relacionada com a baixa freqüência de malária grave pelo P. falciparum. Portanto, os genótipos encontrados no sistema ABO dos indivíduos maláricos e não maláricos pode promover relevantes informações, para o entendimento da epidemiologia da malária grave por P. falciparum na Amazônia brasileira. / Abstract: The ABO blood system (sABO) is the most important system on the blood groups compatibility. Several studies have shown its associations with various infectious diseases, including malaria. This study evaluated the association between the ABO histo-blood genotypes and non-severe malaria caused by Plasmodium falciparum. PCR/RFLP protocol had be used for both ABO blood group system genotyping in malaria suffering individuals and blood donors, from malaria areas of the Brazilian Amazon. The homozygous genotype ABO*O01O01 was prevalent in both malaria and the blood donors. The genotype ABO*AB represented about 3% of the infected population and 5% of non-infected. No statistically significant differences were observed in sABO genotypic and allelic frequencies of patients and the control group, even when individuals were analyzed only with pure infection of P. falciparum. The frequency of sABO in the Brazilian Amazon may be related to the low frequency of non-severe malaria P. falciparum. Therefore, the genotypes found in the ABO blood system in malaric and non-malaric individuals can promote relevant information for the understanding of the severe malaria by P. falciparum epidemiology in the Brazilian Amazon. Keywords: Malaria; ABO blood group system; Plasmodium falciparum. / Orientador: Ricardo Luiz Dantas Machado / Coorientador: Luiz Carlos de Mattos / Banca: Carlos Eugênio Cavasini / Banca: Irineu Luiz Maia / Mestre