Browsing by Author "Oliveira, Maykon Tavares de"

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    Activity of the sesquiterpene lactone goyazensolide against Trypanosoma cruzi in vitro and in vivo.
    (2020) Milagre, Matheus Marques; Branquinho, Renata Tupinambá; Gonçalves, Maíra Fonseca; Assis, Gabriela Maíra Pereira de; Oliveira, Maykon Tavares de; Reis, Levi Eduardo Soares; Guimarães, Dênia Antunes Saúde; Lana, Marta de
    Background: The current drugs for Chagas disease treatment present several limitations Methods: The sesquiterpene lactone goyazensolide (GZL) was evaluated regarding to cytotoxicity and trypanocidal activity against amastigotes, selectivity index (SI) in vitro, acute toxicity and anti-Trypanosoma cruzi activity in vivo. Results: The in vitro cytotoxicity in H9c2 cells was observed at doses >250 ng mL−1 of GZL and the SI were of 52.82 and 4.85 (24 h) and of 915.00 and 41.00 (48 h) for GZL and BZ, respectively. Nephrotoxicity and hepatotoxicity were not verified. Treatment with GZL of mice infected with CL strain led to a significant decrease of parasitaemia and total survival at doses of 1 and 3 mg kg−1 day−1 by oral and IV, respectively. This last group cured 12.5% of the animals (negativation of HC, PCR, qPCR and ELISA). Animals infected with Y strain showed significant decrease of parasitaemia and higher negativation in all parasitological tests in comparison to BZ and control groups, but were ELISA reactive, as well as the BZ group, but mice treated with 5.0 mg kg−1 day−1 by oral were negative in parasitological tests and survived. Conclusion: GZL was more active against T. cruzi than benznidazole in vitro and presented important therapeutic activity in vivo in both T. cruzi strains.
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    Benznidazole, itraconazole and their combination in the treatment of acute experimental chagas disease in dogs.
    (2019) Cunha, Eleonora Lima Alves; Torchelsen, Fernanda Karoline Vieira da Silva; Cunha, Lucas Maciel; Oliveira, Maykon Tavares de; Fonseca, Kátia da Silva; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Lana, Marta de
    Chagas disease (CD) is a serious public health problem in Latin America and its treatment remains neglected. Benznidazole (BZ), the only drug available in Brazil, presents serious side effects and low therapeutic efficacy, especially at the chronic phase. The last clinical trials demonstrated that the first generation of azole compounds were less successful than BZ in CD chemotherapy, which stimulated studies of these compounds associated to BZ and nifurtimox (NF). This study evaluated the therapeutic efficacy of BZ, itraconazole (ITZ) and their combination (BZ + ITZ) in dogs infected with the VL-10 T. cruzi strain in the acute phase of the disease. Twenty young mongrel dogs were inoculated with 2.0 × 103 blood trypomastigotes/kg and divided into four groups: treated with BZ, ITZ and BZ + ITZ for 60 days, and control group (INT). The parasitemia of the BZ + ITZ and BZ groups were similar and showed significant reduction compared to the INT group. The group treated with ITZ also showed significant parasitemia reduction compared to the INT group. The global analysis of hemoculture (HC), blood PCR, conventional serology (CS-ELISA), heart qPCR and histopathology techniques, used in the post-treatment evaluation, revealed that BZ + ITZ combination lead to a more reduction of parasitemia during the acute phase and heart qPCR positivity, less cardiac damage (inflammation and fibrosis in the left ventricle) and total survival. According to the classical cure criteria one animal treated with BZ + ITZ can be considered cured in its final evaluation and two other dogs, one of this group and one treated with ITZ were in process of cure. At least for BZ-resistant T. cruzi strains such as VL-10, BZ + ITZ was not effective to induce parasitological cure or a profound and sustained reduction of the parasite burden in blood and infected organs.
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    Differential expression of proteins in genetically distinct Trypanosoma cruzi samples (TcI and TcII DTUs) isolated from chronic Chagas disease cardiac patients.
    (2018) Oliveira, Maykon Tavares de; Rúbio, Karina Taciana Santos; Neves, Leandro Xavier; Toledo, Max Jean de Ornelas; Borges, William de Castro; Lana, Marta de
    Background Trypanosoma cruzi, a hemoflagellate protozoan parasite and the etiological agent of Chagas disease (CD), exhibits great genetic and biological diversity. Infected individuals may present clinical manifestations with different levels of severity. Several hypotheses have been proposed to attempt to correlate the diversity of clinical signs and symptoms to the genetic variability of T. cruzi. This work aimed to investigate the differential expression of proteins from two distinct genetic groups of T. cruzi (discrete typing units TcI and TcII), isolated from chronically infected individuals displaying the cardiac form of CD. For this purpose, epimastigote forms of the two isolates were cultured in vitro and the cells recovered for protein extraction. Comparative two-dimensional (2D) gel electrophoreses were performed and differentially expressed spots selected for identification by mass spectrometry, followed by database searching and protein categorization. Results The 2D electrophoretic profiles revealed the complex composition of the T. cruzi extracted proteome. Protein spots were distributed along the entire pH and molecular mass ranges attesting for the integrity of the protein preparations. In total, 46 differentially expressed proteins were identified present in 40 distinct spots found in the comparative gel analyses. Of these, 16 displayed upregulation in the gel from TcI-typed parasites and 24 appeared overexpressed in the gel from TcII-typed parasites. Functional characterization of differentially expressed proteins revealed major alterations associated with stress response, lipid and amino acid metabolism in parasites of the TcII isolate, whilst those proteins upregulated in the TcI sample were primarily linked to central metabolic pathways. Conclusions The comparative 2D-gel electrophoresis allowed detection of major differences in protein expression between two T. cruzi isolates, belonging to the TcI and TcII genotypes. Our findings suggest that patients displaying the cardiac form of the disease harbor parasites capable of exhibiting distinct proteomic profiles. This should be of relevance to disease prognosis and treatment.
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    Efficacy of Lychnopholide polymeric nanocapsules after oral and intravenous administration in murine experimental Chagas disease.
    (2016) Mello, Carlos Geraldo Campos de; Branquinho, Renata Tupinambá; Oliveira, Maykon Tavares de; Milagre, Matheus Marques; Guimarães, Dênia Antunes Saúde; Mosqueira, Vanessa Carla Furtado; Lana, Marta de
    The etiological treatment of Chagas disease remains neglected. The compounds available show several limitations, mainly during the chronic phase. Lychnopholide encapsulated in polymeric nanocapsules (LYC-NC) was efficacious in mice infected with Trypanosoma cruzi and treated by intravenous administration during the acute phase (AP). As the oral route is preferred for treatment of chronic infections, such as Chagas disease, this study evaluated the use of oral LYC-NC in the AP and also compared it with LYC-NC administered to mice by the oral and intravenous routes during the chronic phase (CP). The therapeutic efficacy was evaluated by fresh blood examination, hemoculture, PCR, and enzyme-linked immunosorbent assay (ELISA). The cure rates in the AP and CP were 62.5% and 55.6%, respectively, upon oral administration of LYC–poly(D,L-lactide)–polyethylene glycol nanocapsules (LYC-PLA-PEG-NC) and 57.0% and 30.0%, respectively, with LYC–poly- -caprolactone nanocapsules (LYC-PCL-NC). These cure rates were significantly higher than that of free LYC, which did not cure any animals. LYC-NC formulations administered orally during the AP showed cure rates similar to that of benznidazole, but only LYC-NC cured mice in the CP. Similar results were achieved with intravenous treatment during the CP. The higher cure rates obtained with LYC loaded in PLA-PEG-NC may be due to the smaller particle size of these NC and the presence of PEG, which influence tissue diffusion and the controlled release of LYC. Furthermore, PLA-PEG-NC may improve the stability of the drug in the gastrointestinal tract. This work is the first report of cure of experimental Chagas disease via oral administration during the CP. These findings represent a new and important perspective for oral treatment of Chagas disease.
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    Evaluation of parasite and host genetics in two generations of a family with Chagas disease.
    (2018) Lima, Ana Paula Braga; Oliveira, Maykon Tavares de; Silva, Rafael Rodrigues; Torres, Rosália Morais; Veloso, Vanja Maria; Lana, Marta de; Silva, Glenda Nicioli da
    Chagas disease, caused by the protozoan Trypanosoma cruzi, is considered to be a multifactorial disease associated with host and parasite genetics, which influence clinical aspects of the disease and other host conditions. In order to understand better the evolution of the disease, this study intended to evaluation of parasite and host genetics in two generations of a family with Chagas disease from the Alto Paranaiba region, Minas Gerais, Brazil, comprising a mother and her five daughters. Several features were evaluated, including the characterization of T. cruzi directly from the blood of patients, host polymorphisms of genes related to cardiomyopathy (TNF, WISP1, CCR5, and TGF-β1) and clinical aspects of the patients. To verify the intraspecific variability of the parasite, the characterization was done directly from human blood using the PCR-LSSP technique and analyzed based on Dice coefficient and unweighted pair group analysis (UPGMA). The host polymorphism was evaluated by PCR-RFLP. The global results showed low variability of the parasites characterized from blood of patients, through Shannon index (0.492) and mean heterozygosity value per locus (0.322). All six patients presented the same genetic polymorphism profile for TNF, WISP1, and TGF-β1, and only one patient was homozygous to CCR5, which suggests that there is no association between the clinical aspects of the patients and their genetic profiles. In conclusion, the findings confirm that the understanding of the clinical evolution of Chagas disease goes beyond the genetic aspects of the parasite and the host.
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    Experimental benznidazole treatment of Trypanosoma cruzi II strains isolated from children of the Jequitinhonha Valley, Minas Gerais, Brazil, with Chagas disease.
    (2015) Silva, Jaquelline Carla Valamiel de Oliveira e; Assis, Girley Francisco Machado de; Oliveira, Maykon Tavares de; Paiva, Nívia Carolina Nogueira de; Araújo, Márcio Sobreira Silva; Carneiro, Cláudia Martins; Martins Filho, Olindo Assis; Martins, Helen Rodrigues; Lana, Marta de
    Trypanosoma cruzi strains from distinct geographic areas show differences in drug resistance and association between parasites genetic and treatment response has been observed. Considering that benznidazole (BZ) can reduce the parasite burden and tissues damage, even in not cured animals and individuals, the goal is to assess the drug response to BZ of T. cruzi II strains isolated from children of the Jequitinhonha Valley, state of Minas Gerais, Brazil, before treatment. Mice infected and treated with BZ in both phases of infection were compared with the untreated and evaluated by fresh blood examination, haemoculture, polymerase chain reaction, conventional (ELISA) and non-conventional (FC-ALTA) serologies. In mice treated in the acute phase, a significant decrease in parasitaemia was observed for all strains. Positive parasitological and/or serological tests in animals treated during the acute and chronic (95.1-100%) phases showed that most of the strains were BZ resistant. However, beneficial effect was demonstrated because significant reduction (p < 0.05%) and/or suppression of parasitaemia was observed in mice infected with all strains (acute phase), associated to reduction/elimination of inflammation and fibrosis for two/eight strains. BZ offered some benefit, even in not cured animals, what suggest that BZ use may be recommended at least for recent chronic infection of the studied region.
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    Genotipagem de amostras de Trypanosoma cruzi isoladas de pacientes chagásicos de dois municípios da região do Vale do Jequitinhonha, MG, Brasil.
    (Programa de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2012) Oliveira, Maykon Tavares de; Lana, Marta de
    A espécie do Trypanosoma cruzi possui uma estrutura genética que permite a subdivisão intraespecífica em seis grupos genéticos distintos, denominados TcI, TcII, TcIII, TcIV, TcV e TcVI (Zingales et al., 2009) que tem apresentado diferenças frente a distribuição geográfica, propriedades biológicas e susceptibilidade a droga. É conhecido o predomínio das DTU’s TcII e TcVI em diversas regiões Brasileiras, associados tanto ao ciclo doméstico como ao silvestre da Doença e Chagas, e estando intimamente relacionados com as manifestações clínicas graves em pacientes chagásicos crônicos. Conhecendo o predomínio dessas DTU’s no estado de Minas Gerais, trabalhos anteriores do grupo realizando a genotipagem de um número limitado de amostras destas mesmas localidades (municípios de Berilo e José Gonçalves de Minas, Vale do Jequitinhonha, MG) mostrou a presença somente de amostras de T. cruzi II, como ocorre em outras regiões do Brasil. Desse modo, o objetivo principal do estudo foi caracterizar molecularmente amostras de T. cruzi isoladas de pacientes chagásicos crônicos dos municípios de Berilo e José Gonçalves de Minas, Vale do Jequitinhonha, MG, a fim de determinar o perfil genético do parasito circulante nesta região e comparar esses dados com o observado no Brasil e em outras regiões do Cone Sul. Para isto, os parasitos foram isolados dos pacientes através de hemocultura e mantidos em crescimento em meio LIT para obtenção das massas úmidas e posterior extração de DNA e caracterização por cinco diferentes marcadores moleculares. A identificação inicial dos grupos genéticos do T. cruzi foi realizada seguindo o tríplice ensaio proposto por Lewis et al.(2009). Essa metodologia explora a análise em conjunto dos perfis de bandas gerados após a amplificação do domínio D7 do 24Sα rDNA, do perfil de corte gerado após a digestão dos produtos amplificados de dois genes com suas respectivas enzimas de restrição (HSP60/ECORV e GPI/HhaI) via RFLP-PCR. Nesta primeira etapa de caracterização foram identificadas 43 amostras, sendo todas pertencentes ao grupo TcII, segundo a nova classificação consensual proposta por Zingales et al. (2009). Entretanto, oito isolados não puderam ter sua identificação definida baseada nessa metodologia e foram submetidas à análise do polimorfismo do gene da citocromo oxidase subunidade II (CoII), 24Sα rDNA e do espaçador intergênico do mini-exon (SL-IR), que permitiram em conjunto, classificá-las como TcVI. A seguir, a técnica de RAPD foi empregada na avaliação da variabilidade intra-específica dos isolados do T. cruzi empregando 10 iniciadores. Os dados obtidos pela análise dos dez iniciadores, foram submetidos à análise de UPGMA para obtenção do fenograma e os resultados obtidos corroboram os dos outros marcadores na identificação da maioria dos isolados (43) como TcII e dos oito restantes como TcVI, revelando ainda pouca variabilidade no interior desses grupos. Os resultados desse trabalho confirmam dados preliminares obtidos na região em estudo, demonstrando a predominância dos isolados de T. cruzi pertencentes ao grupo TcII no município de Berilo, semelhante ao demonstrado por outros estudos que avaliaram isolados obtidos de pacientes em outras regiões no eixo nordeste-sul do Brasil. Adicionalmente, foram detectados ainda alguns isolados de TcVI cuja ocorrência é mais rara no Brasil, diferentemente de outros países da América do Sul.
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    Host-parasite interactions in chagas disease : genetically unidentical isolates of a single Trypanosoma cruzi strain identified In vitro via LSSP-PCR.
    (2015) Paiva, Nívia Carolina Nogueira de; Vieira, Paula Melo de Abreu; Oliveri, Larissa Maris Rezende; Fonseca, Kátia da Silva; Lana, Gwenaelle Elza Nathalie Pound; Oliveira, Maykon Tavares de; Veloso, Vanja Maria; Reis, Alexandre Barbosa; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
    The present study aims at establishing whether the diversity in pathogenesis within a genetically diverse host population infected with a single polyclonal strain of Trypanosoma cruzi is due to selection of specific subpopulations within the strain. For this purpose we infected Swiss mice, a genetically diverse population, with the polyclonal strain of Trypanosoma cruzi Berenice-78 and characterized via LSSP-PCR the kinetoplast DNA of subpopulations isolated from blood samples collected from the animals at various times after inoculation (3, 6 and 12 months after inoculation). We examined the biological behavior of the isolates in acellular medium and in vitro profiles of infectivity in Vero cell medium. We compared the characteristics of the isolates with the inoculating strain and with another strain, Berenice 62, isolated from the same patient 16 years earlier. We found that one of the isolates had intermediate behavior in comparison with Berenice-78 and Berenice-62 and a significantly different genetic profile by LSSP-PCR in comparison with the inoculating strain. We hereby demonstrate that genetically distinct Trypanosoma cruzi isolates may be obtained upon experimental murine infection with a single polyclonal Trypanosoma cruzi strain.
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    Lychnopholide in PLA-PEG nanocapsules cures infection by drug resistant Trypanosoma cruzi strain in acute and chronic phases.
    (2020) Branquinho, Renata Tupinambá; Mello, Carlos Geraldo Campos de; Oliveira, Maykon Tavares de; Reis, Levi Eduardo Soares; Vieira, Paula Melo de Abreu; Guimarães, Dênia Antunes Saúde; Mosqueira, Vanessa Carla Furtado; Lana, Marta de
    Chagas disease remains neglected, and current chemotherapeutics present severe limitations. Lychnopholide (LYC) at low doses loaded in polymeric poly(d,l-lactide)-block-polyethylene glycol (PLA-PEG) nanocapsules (LYC-PLA-PEG-NC) exhibits anti-Trypanosoma cruzi efficacy in mice infected with a partially drug-resistant strain. This study reports the efficacy of LYC-PLA-PEG-NC at higher doses in mice infected with a T. cruzi strain resistant to benznidazole (BZ) and nifurtimox (NF) treated at both the acute phase (AP) and the chronic phase (CP) of infection by the oral route. Mice infected with the T. cruzi VL-10 strain were treated by the oral route with free LYC (12 mg/kg of body weight/day), LYC-PLA-PEG-NC (8 or 12 mg/kg/day), or BZ at 100 mg/kg/day or were not treated (controls). Treatment efficacy was assessed by hemoculture (HC), PCR, enzyme-linked immunosorbent assay (ELISA), heart tissue quantitative PCR (qPCR), and histopathology. According to classical cure criteria, treatment with LYC-PLA-PEG-NC at 12 mg/kg/day cured 75% (AP) and 88% (CP) of the animals, while at a dose of 8 mg/kg/day, 43% (AP) and 43% (CP) were cured, showing dose-dependent efficacy. The negative qPCR results for heart tissue and the absence of inflammation/fibrosis agreed with the negative results obtained by HC and PCR. Thus, the mice treated with the highest dose could be considered 100% cured, in spite of a low ELISA reactivity in some animals. No cure was observed in animals treated with free LYC or BZ or the controls. These results are exceptional in terms of experimental Chagas disease chemotherapy and provide evidence of the outstanding contribution of nanotechnology in mice infected with a T. cruzi strain totally resistant to BZ and NF at both phases of infection. Therefore, LYC-PLA-PEG-NC has great potential as a new treatment for Chagas disease and deserves further investigations in clinical trials.
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    Lychnopholide in Poly(D,L-Lactide)-block-polyethylene glycol nanocapsules cures infection with a drug-resistant Trypanosoma cruzi strain at acute and chronic phases.
    (2020) Branquinho, Renata Tupinambá; Mello, Carlos Geraldo Campos de; Oliveira, Maykon Tavares de; Reis, Levi Eduardo Soares; Vieira, Paula Melo de Abreu; Guimarães, Dênia Antunes Saúde; Mosqueira, Vanessa Carla Furtado; Lana, Marta de
    Chagas disease remains neglected, and current chemotherapeutics present severe limitations. Lychnopholide (LYC) at low doses loaded in polymeric poly(D,L-lactide)-block-polyethylene glycol (PLA-PEG) nanocapsules (LYC-PLA-PEG-NC) exhibits anti-Trypanosoma cruzi efficacy in mice infected with a partially drugresistant strain. This study reports the efficacy of LYC-PLA-PEG-NC at higher doses in mice infected with a T. cruzi strain resistant to benznidazole (BZ) and nifurtimox (NF) treated at both the acute phase (AP) and the chronic phase (CP) of infection by the oral route. Mice infected with the T. cruzi VL-10 strain were treated by the oral route with free LYC (12 mg/kg of body weight/day), LYC-PLA-PEG-NC (8 or 12 mg/kg/day), or BZ at 100 mg/kg/day or were not treated (controls). Treatment efficacy was assessed by hemoculture (HC), PCR, enzyme-linked immunosorbent assay (ELISA), heart tissue quantitative PCR (qPCR), and histopathology. According to classical cure criteria, treatment with LYC-PLA-PEG-NC at 12 mg/kg/day cured 75% (AP) and 88% (CP) of the animals, while at a dose of 8 mg/kg/day, 43% (AP) and 43% (CP) were cured, showing dose-dependent efficacy. The negative qPCR results for heart tissue and the absence of inflammation/fibrosis agreed with the negative results obtained by HC and PCR. Thus, the mice treated with the highest dose could be considered 100% cured, in spite of a low ELISA reactivity in some animals. No cure was observed in animals treated with free LYC or BZ or the controls. These results are exceptional in terms of experimental Chagas disease chemotherapy and provide evidence of the outstanding contribution of nanotechnology in mice infected with a T. cruzi strain totally resistant to BZ and NF at both phases of infection. Therefore, LYC-PLA-PEG-NC has great potential as a new treatment for Chagas disease and deserves further investigations in clinical trials.
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    Molecular and biological characterization of Trypanosoma cruzi strains isolated from children from Jequitinhonha Valley, State of Minas Gerais, Brazil.
    (2013) Silva, Jaquelline Carla Valamiel de Oliveira e; Assis, Girley Francisco Machado de; Oliveira, Maykon Tavares de; Valadares, Helder Magno Silva; Valle, Ítalo Faria do; Paiva, Nívia Carolina Nogueira de; Martins, Helen Rodrigues; Lana, Marta de
    The biological diversity of Trypanosoma cruzi strains plays an important role in the clinical and epidemiological features of Chagas disease. Methods: Eight T. cruzi strains isolated from children living in a Chagas disease vector-controlled area of Jequitinhonha Valley, State of Minas Gerais, Brazil, were genetically and biologically characterized. Results: The characterizations demonstrated that all of the strains belonged to T. cruzi II, and showed high infectivity and a variable mean maximum peak of parasitemia. Six strains displayed low parasitemia, and two displayed moderate parasitemia. Later peaks of parasitemia and a predominance of intermediate and large trypomastigotes in all T. cruzi strains were observed. The mean prepatent period was relatively short (4.2±0.25 to 13.7±3.08 days), whereas the patent period ranged from 3.3±1.08 to 34.5±3.52 days. Mortality was observed only in animals infected with strain 806 (62.5%). Histopathological analysis of the heart showed that strains 501 and 806 caused infl ammation, but fi brosis was observed only in animals infected with strain 806. Conclusions: The results indicate the presence of an association between the biological behavior in mice and the genetic characteristics of the parasites. The study also confi rmed general data from Brazil where T. cruzi II lineage is the most prevalent in the domiciliary cycle and generally has low virulence, with some strains capable of inducing infl ammatory processes and fi brosis.
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    Propriedades biológicas fundamentais de diferentes grupos genéticos do Trypanosoma cruzi, e avaliação inicial da investigação da expressão diferencial de proteínas associadas aos grupos genéticos TcI e TcII.
    (2016) Oliveira, Maykon Tavares de; Lana, Marta de; Borges, William de Castro; Lana, Marta de; Silva, André Talvani Pedrosa da; Menezes, Evandro Marques de; Veloso, Vanja Maria; Silva, Rosiane Aparecida da
    A Doença de Chagas (DCh) tem como agente etiológico o protozoário hemoflagelado Trypanosoma cruzi que apresenta grande diversidade genética, que por sua vez apresenta-se relacionada à diversidade biológica da espécie. Diversas estudo foram conduzidos ao longo do tempo, na tentativa de relacionar a variabilidade genética do T. cruzi com seus parâmetros biológicos resistência ao tratamento e as diferentes manifestações clínicas da DCh, mas até o presente momento sem sucesso. Sabendo-se da importância e necessidade de busca de novos alvos que possam responder a essas questões, a proposta desse projeto foi avaliar os parâmetros biológicos principais de seis amostras do T. cruzi, pertencentes a grupos genéticos distintos (TcI, TcII e TcVI), isoladas de pacientes chagásicos crônicos, apresentando formas clínicas distintas da DCh. Foram utilizadas ferramentas proteômicas para determinar o proteoma diferencial de duas amostras do T. cruzi (TcI e TcII) para verificar se há correlação entre o perfil proteico com os parâmetros biológicos, evolução da infecção em modelo murino e as formas clínicas da doença humana. Este trabalho avaliou ainda a biologia de todas as seis amostras em meio acelular (LIT), em células “Vero” e camundongos Swiss. Neste modelo animal foi também avaliada a resposta ao tratamento com o Nifurtimox nas fases aguda e crônica da infecção. O conjunto de dados biológicos tais como crescimento em meio acelular, infecção em meio celular e desenvolvimento da infecção em modelo murino, obtidos de cada amostra de T. cruzi revelou diferenças significativas entre os genótipos. Em relação à resposta ao tratamento etiológico, o critério de cura clássico (ELISA negativa), demonstrou cura em apenas 6,25% dos animais infectados e tratados na fase aguda (ITFA). Em contrapartida, quando foi adotado um critério mais recente (CF-AATV negativa), o índice de cura foi 10 vezes maior (62.5%), e os mesmos animais considerados curados por este segundo critério foram também negativos na qPCR em tecido cardíaco. Na fase crônica, nenhuma amostra foi curada considerando ambos os critérios de cura, e a qPCR no coração também foi positiva em todos os animais, confirmando a conhecida dificuldade de curar infecções crônicas. Os dados obtidos da proteômica das duas cepas (TcI e TcII) a partir das formas epimastigotas, demonstraram diferenças significativas na expressão diferencial de proteínas, principalmente em relação ao grupo proteico com função de resposta ao estresse. Dessa forma, pode-se cloncuir com esse trabalho, que a hipótese de correlação entre genética do T. cruzi com a biologia das amostras foi confirmada, e que é importante adotar metodologias mais atuais que antecipam a demonstração da cura parasitológica da DCh. Esse trabalho demonstrou ainda a importância de busca de alvos diferencialmente expressos no parasita que sirvam como marcadores de prognóstico da infecção experimental e da DCh humana.
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    TcI, TcII and TcVI Trypanosoma cruzi samples from Chagas diseasepatients with distinct clinical forms and critical analysis of in vitro andin vivo behavior, response to treatment and infection evolution inmurine model.
    (2017) Oliveira, Maykon Tavares de; Branquinho, Renata Tupinambá; Alessio, Glaucia Diniz; Mello, Carlos Geraldo Campos de; Paiva, Nívia Carolina Nogueira de; Carneiro, Cláudia Martins; Toledo, Max Jean de Ornelas; Reis, Alexandre Barbosa; Martins Filho, Olindo Assis; Lana, Marta de
    tThe clonal evolution of Trypanosoma cruzi sustains scientifically the hypothesis of association betweenparasite’s genetic, biological behavior and possibly the clinical aspects of Chagas disease in patientsfrom whom they were isolated. This study intended to characterize a range of biological properties ofTcI, TcII and TcVI T. cruzi samples in order to verify the existence of these associations. Several biologicalfeatures were evaluated, including in vitro epimastigote-growth, “Vero”cells infectivity and growth, alongwith in vivo studies of parasitemia, polymorphism of trypomastigotes, cardiac inflammation, fibrosis andresponse to treatment by nifurtimox during the acute and chronic murine infection. The global resultsshowed that the in vitro essays (acellular and cellular cultures) TcII parasites showed higher values for allparameters (growth and infectivity) than TcVI, followed by TcI. In vivo TcII parasites were more virulentand originated from patients with severe disease. Two TcII isolates from patients with severe pathologywere virulent in mice, while the isolate from a patient with the indeterminate form of the disease causedmild infection. The only TcVI sample, which displayed low values in all parameters evaluated, was alsooriginated of an indeterminate case of Chagas disease. Response to nifurtimox was not associated toparasite genetic and biology, as well as to clinical aspects of human disease. Although few number of T.cruzi samples have been analyzed, a discreet correlation between parasite genetics, biological behaviorin vitro and in vivo (murine model) and the clinical form of human disease from whom the samples wereisolated was verified.
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    Trypanosoma cruzi Discret Typing Units (TcII and TcVI) in samples of patients from two municipalities of the Jequitinhonha Valley, MG, Brazil, using two molecular typing strategies.
    (2015) Oliveira, Maykon Tavares de; Assis, Girley Francisco Machado de; Silva, Jaquelline Carla Valamiel de Oliveira e; Machado, Evandro Marques de Menezes; Silva, Glenda Nicioli da; Veloso, Vanja Maria; Macedo, Andréa Mara; Martins, Helen Rodrigues; Lana, Marta de
    Background: Trypanosoma cruzi is classified into six discrete taxonomic units (DTUs). For this classification, different biological markers and classification criteria have been used. The objective was to identify the genetic profile of T. cruzi samples isolated from patients of two municipalities of Jequitinhonha Valley, MG, Brazil. Methods: Molecular characterization was performed using two different criteria for T. cruzi typing to characterize 63 T. cruzi samples isolated from chronic Chagas disease patients. The characterizations followed two distinct methodologies. Additionally, the RAPD technique was used to evaluate the existence of genetic intragroup variability. Results: The first methodology identified 89 % of the samples as TcII, but it was not possible to define the genetic identity of seven isolates. The results obtained with the second methodology corroborated the classification as TcII of the same samples and defined the classification of the other seven as TcVI. RAPD analysis showed lower intra-group variability in TcII. Conclusions: The results confirmed the preliminary data obtained in other municipalities of the Jequitinhonha Valley, showing a predominance of TcII, similar to that verified in northeast/south axis of Brazil and the first detection of TcVI in the study region. The second protocol was more simple and reliable to identify samples of hybrid character.