Browsing by Author "Roatt, Bruno Mendes"
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Item Acarbose presents in vitro and in vivo antileishmanial activity against Leishmania infantum and is a promising therapeutic candidate against visceral leishmaniasis.(2020) Costa, Rafaella R.; Silva, João Augusto Oliveira da; Reis, Thiago Alves Rosa dos; Tavares, Grasiele de Sousa Vieira; Mendonça, Débora Vasconcelos Costa; Freitas, Camila Simões de; Lage, Daniela Pagliara; Martins, Vívian Tamietti; Antinarelli, Luciana Maria Ribeiro; Machado, Amanda Sanchez; Bandeira, Raquel Soares; Ribeiro, Fernanda Ludolf; Santos, Thaís Teodoro de Oliveira; Brito, Rory Cristiane Fortes de; Humbert, Maria Victoria; Souza, Daniel Menezes; Duarte, Mariana Costa; Chávez Fumagalli, Miguel Angel; Roatt, Bruno Mendes; Coimbra, Elaine Soares; Coelho, Eduardo Antônio FerrazTreatment against visceral leishmaniasis (VL) is mainly hampered by drug toxicity, long treatment regimens and/or high costs. Thus, the identifcation of novel and low-cost antileishmanial agents is urgent. Acarbose (ACA) is a specifc inhibitor of glucosidase-like proteins, which has been used for treating diabetes. In the present study, we show that this molecule also presents in vitro and in vivo specifc antileishmanial activity against Leishmania infantum. Results showed an in vitro direct action against L. infantum promastigotes and amastigotes, and low toxicity to mammalian cells. In addition, in vivo experiments performed using free ACA or incorporated in a Pluronic® F127-based polymeric micelle system called ACA/ Mic proved efective for the treatment of L. infantum-infected BALB/c mice. Treated animals presented signifcant reductions in the parasite load in their spleens, livers, bone marrows and draining lymph nodes when compared to the controls, as well as the development of antileishmanial Th1-type humoral and cellular responses based on high levels of IFN-γ, IL-12, TNF-α, GM-CSF, nitrite and IgG2a isotype antibodies. In addition, ACA or ACA-treated animals sufered from low organ toxicity. Treatment with ACA/Mic outperformed treatments using either Miltefosine or free ACA based on parasitological and immunological evaluations performed one and 15 days post-therapy. In conclusion, data suggest that the ACA/Mic is a potential therapeutic agent against L. infantum and merits further consideration for VL treatment.Item An 8-hydroxyquinoline-containing polymeric micelle system is effective for the treatment of murine tegumentary leishmaniasis.(2016) Lage, Letícia Martins dos Reis; Barichello, José Mario; Lage, Daniela Pagliara; Mendonça, Débora Vasconcelos Costa; Carvalho, Ana Maria Ravena Severino; Rodrigues, Marcella Rezende; Souza, Daniel Menezes; Roatt, Bruno Mendes; Alves, Ricardo José; Tavares, Carlos Alberto Pereira; Coelho, Eduardo Antônio Ferraz; Duarte, Mariana CostaItem Analysis using canine peripheral blood for establishing in vitro conditions for monocyte differentiation into macrophages for Leishmania chagasi infection and T-cell subset purification.(2013) Viana, Kelvinson Fernandes; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno Mendes; Resende, Lucilene Aparecida; Lemos, Denise da Silveira; Oliveira, Rodrigo Corrêa de; Martins Filho, Olindo Assis; Moura, Sandra Aparecida Lima de; Zanini, Marcos Santos; Araújo, Márcio Sobreira Silva; Reis, Alexandre Barbosa; Giunchetti, Rodolfo CordeiroCanine visceral leishmaniasis (CVL) is a parasitic disease endemic in many countries, anddogs present as the major natural reservoir of the parasite, Leishmania chagasi (syn. L.infantum). Biomarkers in the canine immune system is an important technique in thecourse of developing vaccines and treatment strategies against CVL. New methodologiesfor studying the immune response of dogs during Leishmania infection and after receivingvaccines and treatments against CVL would be useful. In this context, we used peripheralblood mononuclear cells (PBMCs) from healthy dogs to evaluate procedures related to (i)establishment of in vitro conditions of monocytes differentiated into macrophages infectedwith L. chagasi and (ii) purification procedures of T-cell subsets (CD4+and CD8+) usingmicrobeads. Our data demonstrated that after 5 days of differentiation, macrophages wereable to induce significant phagocytic and microbicidal activity after L. chagasi infectionand also showed increased frequency of parasitism and a higher parasite load. Although N-acetyl- _-d-glucosaminidase (NAG) levels presented similar levels of macrophage cultureand L. chagasi infection, a progressive decrease in myeloperoxidase (MPO) levels was ahallmark over 5 days of culture. High purity levels (>90%) of CD4 and CD8 T cells wereobtained on a magnetic separation column. We concluded that monocytes differentiatedinto macrophages at 5 days and displayed an intermediate frequency of parasitism andparasite load 72 h after L. chagasi infection. Furthermore, the purification system usingcanine T-lymphocyte subsets obtained after 5 days of monocyte differentiation provedefficient for CD4 or CD8 T-cell purification (≥90%). The in vitro analysis using L. chagasi-infected macrophages and purified T cells presented a prospective methodology that couldbe incorporated in CVL vaccine and treatment studies that aim to analyze the microbicidalpotential induced by specific CD4+and/or CD8+T cells.Item Association between mast cells, tissue remodelation and parasite burden in the skin of dogs with visceral leishmaniasis.(2017) Cardoso, Jamille Mirelle de Oliveira; Ker, Henrique Gama; Soares, Rodrigo Dian de Oliveira Aguiar; Moreira, Nádia das Dores; Mathias, Fernando Augusto Siqueira; Reis, Levi Eduardo Soares; Roatt, Bruno Mendes; Vieira, Paula Melo de Abreu; Vital, Wendel Coura; Carneiro, Cláudia Martins; Reis, Alexandre BarbosaCanine visceral leishmaniosis (CVL) is a zoonosis of major public health impact caused by organisms of the genus Leishmania which is transmitted to human and animals by phlebotomine sand flies. The skin is the first point of contact with Leishmania parasites for sandy fly vectors and it is considered an important reservoir compartment in infected dogs. The aim of this study was to determine the main histophatologic alterations in ear skin of dogs naturally infected by Leishmania infantum with different clinical status and different degrees of parasitism. Therefore, thirty-four dogs naturally infected with L. infantum were grouped according to their clinical status in asymptomatic (AD, n =11), oligosymptomatic (OD, n=11) and symptomatic dogs (SD, n=12) as well as their degrees of parasite load in the skin as low (LP, n=11), median (MP, n= 11) and high (HP, n=12) parasitism. Additionally, ten dogs were used as control (CD, n =10). At necropsy, skin samples were collected for further histological and parasitological analysis. The OD and SD groups presented higher parasite burden than AD group. The inflammation was higher in SD group when compared to OD and AD. The LP, MP and HP groups showed an increasing inflammatory process, indicating that a great parasite load is accompanied by a major inflammatory process in the skin. The number of mast cells was higher in the OD and LP groups than CD group, suggesting that these cells may be involved in tissue remodeling, since that an increase of type III collagen fibers and decrease type I collagen fibers were observed in these groups. Taken together, our results enable a better understanding of the alterations in skin of CVL dogs and consequently new insights about the pathogenesis of CVL.Item Atividade reguladora da via de degradação extracelular de nucleotídeos de adenina na virulência de diferentes cepas e formas evolutivas de Trypanosoma cruzi in vitro e in vivo.(2020) Leite, Ana Luísa Junqueira; Silva, André Talvani Pedrosa da; Silva, André Talvani Pedrosa da; Roatt, Bruno Mendes; Silva, Eduardo de Almeida Marques da; Bressan, Gustavo Costa; Borges, William de CastroPopulações distintas de Trypanosoma cruzi interagem com células musculares cardíacas de mamíferos, causando diferentes padrões de inflamação e baixa funcionalidade do coração. Durante a infecção pelo T. cruzi, o ATP extracelular é hidrolisado em seu componente monofosfatado (AMP), com base na infectividade, virulência e regulação da resposta inflamatória. T. cruzi realiza essa hidrólise através da ectonucleotidase, TcNTPDase-1. Este estudo teve como objetivo avaliar o papel da via de degradação extracelular de nucleotídeos de adenina em culturas ricas em formas tripomastigotas metacíclicas (CTM) e formas tripomastigotas derivadas de cultura celular (TC) das cepas Colombiana (unidade de tipagem discreta - DTU I), VL-10 (DTU II) e CL (DTU VI) de T. cruzi. Para isso, medimos a atividade da ectonucleotidase no parasito e realizamos a infecção em células J774 infectadas e em camundongos C57BL/6 infectados com parasitos pré-tratados ou não com suramina para avaliar o perfil cardíaco parasitário e inflamatório na fase aguda da infecção. Nossos dados indicaram uma atividade mais alta para hidrólise de ATP no CTM da cepa Colombiana em comparação com as das cepas VL-10 e CL. A TC da cepa CL apresentou maior capacidade de hidrolisar o ATP do que as cepas Colombiana e VL-10. A suramina inibiu a hidrólise de ATP em todas as formas e cepas do parasito estudadas. A infecção em células J774 com parasitos pré-tratados com suramina foi reduzida e aumentou a produção de nitrito in vitro. Estudos in vivo mostraram uma redução do infiltrado inflamatório no tecido cardíaco de animais infectados com TC da cepa Colombiana prétratado com suramina. Em conclusão, a atividade dessa ectonucleotidase nas formas tripomastigotas direciona parte das características biológicas observadas em DTUs distintas e pode induzir patogênese cardíaca durante a infecção por T. cruzi.Item Avaliação da terapia com células tronco mesenquimais da medula óssea na cardiopatia chagásica de cães infectados por Trypanosoma cruzi.(2019) Nascimento, Alvaro Fernando da Silva do; Bahia, Maria Terezinha; Carvalho, Adriana Bastos; Bahia, Maria Terezinha; Roatt, Bruno Mendes; Guedes, Paulo Marcos da Matta; Santos, Silvana Maria Elói; Lima, Wanderson Geraldo deNeste estudo foi avaliada a eficácia das células-tronco mesenquimais (MSCS) de medula óssea, isoladamente ou em combinação com a terapia convencional para insuficiência cardíaca, no tratamento da cardiopatia chagásica crônica. Cães infectados com a cepa VL-10 de Trypanosoma cruzi foram tratados com MSCs de origem autóloga ou alogeneicas. Os animais receberam, em dose única, por via intravenosa, 5 milhões de células/kg entre 6 a 8 meses após a infecção. Adicionalmente, outros grupos de animais receberam o tratamento farmacológico (enalapril 5mg e carvedilol 3,125mg) associado ou não à terapia celular. A avaliação da função cardíaca foi realizada através de ecocardiografias seriadas (antes e 45, 90 e 180 dias após o tratamento). O efeito da terapia celular na intensidade das lesões teciduais foi avaliado por análise quantitativa de miocardite e fibrose no tecido muscular cardíaco (câmaras cardíacas, ápice e septo interventricular) dos animais necropsiados 6-8 meses após os tratamentos. A função sistólica, avaliada pela fração de ejeção, não apresentou diferença significativa entre os animais dos diversos grupos experimentais ao longo do período avaliado. No entanto, a comparação dos valores de FEVE obtidos antes e seis meses após o tratamento mostra diferentes padrões de evolução da função sistólica entre os animais dos diversos grupos experimentais. Os animais não infectados mantiveram a FEVE acima de 40% durante o período de avaliação. Os animais dos grupos MSCAUT, MSCAUT+TF e TF não apresentaram alterações acentuadas na função sistólica no período de acompanhamento. Por outro lado, entre os animais do grupo MSCALO foi observada a redução da percentagem de animais com disfunção sistólica (55% para 22%). Em contraste, um aumento da percentagem de animais com disfunção sistólica (30% para 60%) foi detectado entre animais infectados e não tratados. Além disso, se apenas animais com disfunção sistólica no período prétratamento forem considerados, uma melhora significativa na função sistólica dos animais tratados com MCSALO, em relação aos animais infectados e não tratados, pode ser observada. Em concordância, o tratamento com MSCs foi capaz de reduzir significativamente a miocardite e a fibrose na maioria das regiões cardíacas avaliadas. Além disso, foi observada a redução da apoptose e o aumento da mitose no átrio direito dos animais tratados com MSCS em relação aos animais infectados e não tratados. Diferentemente, o tratamento farmacológico foi capaz induzir a redução da apoptose, mas não de aumentar a mitose no átrio direito dos animais. Em seguida, foi avaliada a expressão dos fatores de transcrição associados às linhagens de células T efetoras Th1 e Th2. Os resultados desta avaliação mostraram que a infecção por T. cruzi induziu uma expressão aumentada de mRNA dos marcadores de resposta Th1 e Th2 no átrio direito de animais. O perfil de resposta imune induzido pela infecção por T. cruzi não foi alterado pelo tratamento com MSCAUT, MSCAUT+TF ou TF. Por outro lado, expressões reduzidas de mRNA para T-bet, IFN-γ, TNFα, CCL5 / CCR5 e expressão aumentada de mRNA para IL-10 foram detectadas no tecido (átrio direito) dos animais tratados com MSCALO. Em geral, os resultados deste estudo mostraram o efeito benéfico do tratamento da cardiopatia chagásica com MSCs, especialmente com MSCS de origem alogeneica. Entretanto, novos estudos, utilizando um maior número de animais com disfunção sistólica no momento do tratamento, devem ser realizados para confirmar o por T. cruzi.Item Avaliação de quimeras como candidatos vacinais em modelo hamster (Mesocricetus auratus) desafiados por Leishmania infantum.(2020) Gusmão, Miriã Rodrigues; Roatt, Bruno Mendes; Brito, Rory Cristiane Fortes de; Roatt, Bruno Mendes; Souza, Daniel Menezes; Béla, Samantha RibeiroA leishmaniose visceral é considerada a mais grave dentre as formas clínicas das leishmanioses e até o presente momento não há uma vacina que possa ser empregada em campanhas de controle e profilaxia dessa doença. No intuito de aprimorar estratégias para o desenvolvimento de vacinas, a vacinologia reversa, por meio da imunoinformática é uma moderna tecnologia que aborda metodologias computacionais para a busca de novos alvos e candidatos vacinais. Em um estudo prévio do nosso grupo de pesquisa, duas quimeras foram desenhadas empregando a estratégia da imunoinformática, Quimera A e Quimera B, e quando associadas ao adjuvante saponina, apresentaram resultados promissores em modelo murino. Entretanto, este modelo não reflete a evolução clínica observada em cães e humanos infectados pelo parasito. Neste sentido, é fundamental avaliar estes potenciais imunobiológicos em um modelo experimental que desenvolva de forma semelhante aspectos, clínicos-patológicos, imunológicos e parasitológicos observados em cães e humanos durante a progressão da LV. Desse modo, o objetivo deste trabalho foi avaliar a imunogenicidade e eficácia das quimeras isoladas e/ou associadas ao sistema de adjuvantes saponina e monofosforil lipídeo A (MPL) em modelo hamster (M. auratus) desafiados com L. infantum. Os animais foram divididos em seis grupos experimentais compreendendo: grupo salina (SAL), sitema de adjuvantes saponina e MPL (SM), quimera A (QA), quimera A associada a saponina+MPL (QASM), quimera B (QB) e quimera B associada a saponina+MPL (QBSM). Esses animais foram imunizados com três doses de cada uma das composições vacinais em intervalos de 15 dias entre as doses. Após 21 dias da última dose, os hamsters foram desafiados com promastigotas de L. infantum em fase estacionária de crescimento, pela via intraperitoneal e após 60 dias os animais foram necropsiados. Amostras de sangue, soro, fragmentos do baço foram obtidos para a realização de diferentes análises laboratoriais através de análises hematológicas, bioquímicas, imunológicas e parasitológicas. Em relação às análises hemato-bioquímicas, observamos que os grupos imunizados apresentaram parâmetros de leucograma, eritrograma e das funções renais, hepáticas e proteinograma normais. Entretanto, foram observadas nos grupos controle (SAL) e sistema de adjuvantes (SM) queda nos valores de plaquetas e alterações nas dosagens hepáticas, principalmente de ALT. A análise da resposta humoral pelo perfil de IgG-total anti-Leishmania, evidenciou uma redução na reatividade desse anticorpo nos grupos imunizados em relação aos grupos controles. Além disso, foi evidenciado nos grupos imunizados uma elevada resposta próinflamatória de esplenócitos com aumento da produção de citocinas como IFN- e TNF-, tanto por linfócitos totais e pela subpopulação CD4+ , bem como uma redução na produção da citocina IL-10 por estas células. As vacinas demonstraram eficácia constatada pela redução do parasitismo esplênico nos grupos imunizados chegando a mais de 90% de redução da carga parasitária o que pode estar relacionado também com a alta produção de óxido nítrico (NO) encontrada nesses grupos. Dessa forma, os resultados obtidos no presente trabalho sugerem o potencial de imunogenicidade e proteção das quimeras avaliadas, a relevância da utilização do hamster como modelo experimental para LV, bem como a importância de novas estratégias como a imunoinformática para o desenvolvimento de vacinas para a LV.Item Avaliação de uma vacina terapêutica (LBMPL) no tratamento da leishmaniose visceral utilizando o cão naturalmente infectado com Leishmania infantum como modelo experimental.(2013) Roatt, Bruno Mendes; Reis, Alexandre BarbosaA leishmaniose visceral (LV) é uma das doenças mais negligenciadas no mundo, que afeta principalmente os países mais pobres. Epidemias urbanas de LV são observadas em várias cidades do Brasil e a doença tem sido verificada como infecção oportunista em pacientes com AIDS. Estima-se que a infecção HIV/L. infantum aumenta o risco em 100 a 2.320 vezes de se desenvolver uma LV grave. Atualmente, diversos são os relatos do surgimento de cepas resistentes do parasito aos fármacos convencionais. Sendo assim, o desenvolvimento de novas estratégias profiláticas/terapêuticas (imunofármacos) contra a doença se faz necessário e urgente. Neste contexto, muitos modelos animais experimentais já foram avaliados e o cão, se destaca como um dos melhores modelos experimentais para o estudo da LV humana (LVH) bem como seu emprego em ensaios pré-clínicos, pois apresenta características clínico-patológicas e uma história natural de doença extremamente semelhantes à LVH ativa e grave. Dessa forma, nosso estudo buscou avaliar a estratégia de tratamento empregando uma vacina terapêutica composta por antígenos totais de L. braziliensis associada ao adjuvante MPL (vacina LBMPL) para LVH empregando cães sintomáticos, naturalmente infectados por L. infantum. Assim, 16 cães infectados foram subdivididos em dois grupos experimentais: um grupo que recebeu como imunoterapia o adjuvante monofosforil lipídeo A apenas, sendo considerado grupo controle (MPL; n=6) e outro que recebeu como imunoterapia a vacina composta por antígenos de L. braziliensis associada ao adjuvante MPL (LBMPL n=10). Os animais foram submetidos a um esquema imunoterapêutico composto por 3 séries de tratamento, cada série de 10 doses com concentrações crescentes do antígeno vacinal (60μg – 300μg de antígeno protéico + 5μg - 25μg de MPL (dias 1-5) e / 300μg Ag + 25μg MPL (dias 6-10) 1ª série / 300μg Ag + 25μg MPL 2ª e 3ª séries) sob a via subcutânea com intervalo de 10 dias de descanso entre cada série. Os cães foram avaliados antes de serem tratados (T0) e após 15 (T15), 30 (T30) e 90 (T90) dias do tratamento sob os aspectos hemato-bioquímicos, imunológicos, clínicos e parasitológicos. Nossos principais resultados revelaram que a imunoterapia com a vacina LBMPL foi capaz de restabelecer e normalizar as principais alterações hematológicas (eritrócitos, hemoglobina, hematócrito e plaquetas) e bioquímicas (uréia, AST ou TGO, fosfatase alcalina, bilirrubina, e proteína total) decorrentes da LVC e presentes antes do tratamento. Além disso, cães imunotratados com a vacina LBMPL responderam na avaliação ex vivo, com aumento de linfócitos T CD3+ e suas subpopulações (T CD4+ e T CD8+), redução de linfócitos B CD21+, redução na razão T CD4+/T CD8+, aumento da razão LT/LB, aumento de células NK CD5-CD16+ e aumento de monócitos CD14+ circulantes como principais biomarcadores celulares de sucesso terapêutico no sangue periférico. Já no contexto das avaliações in vitro, animais submetidos à vacinoterapia com LBMPL desenvolveram forte memória imunológica antígeno-específica, capaz de induzir elevada atividade linfoproliferativa frente ao estímulo com antígeno solúvel de L. infantum (ASLi) acompanhado por reconhecimento preferencial de células T CD4+ e T CD8+-ASLi específicas. Interessantemente, foi também observado aumento tanto de linfócitos T CD4+IFN-+ e T CD8+IFN-+ bem como redução de linfócitos T CD4+ IL-4+ e T CD8+ IL-4+ após estimulação com ASLi e aumento na produção/secreção de citocinas pró-inflamatórias como TNF- e redução na produção de citocinas imunomodulatórias como IL-10 por células mononucleares do sangue periférico (CMSP); citocina esta, responsável pela imunopatogênese da LV grave. Estes achados caracterizam perfil de resistência a infecção por Leishmania e resposta positiva ao tratamento nos cães imunotratados com a vacina terapêutica LBMPL. De forma surpreendente, em relação aos sinais clínicos sugestivos de LVC, os animais imunotratados com LBMPL apresentaram redução drástica na intensidade e na quantidade de sinais/sintomas clínicos da LV, aumento da massa corporal além de redução da esplenomegalia avaliada clinicamente e por ultrassom, fatores estes intimamente associados ao sucesso terapêutico na doença humana. Somado-se a isso, a vacina LBMPL promoveu ainda uma redução da carga parasitária, avaliada aqui pela PCR em Tempo Real (qPCR), na medula óssea, baço e pele nos cães infectados, sendo até mesmo possível observar em alguns animais ausência de parasitismo nestes órgãos. Os resultados obtidos no presente estudo, confirmam e reafirmam a indicação do cão naturalmente infectado com L. infantum, como modelo experimental pré-clínico de altíssimo valor na leishmaniose visceral. Além disto, nossos resultados permitem também sugerir o uso da imunoterapia com a vacina terapêutica LBMPL como uma potencial proposta de tratamento na leishmaniose visceral canina e/ou humana.Item Canine visceral leishmaniasis : incidence and risk factors for infection in a cohort study in Brazil.(2013) Vital, Wendel Coura; Reis, Alexandre Barbosa; Reis, Levi Eduardo Soares; Braga, Samuel Leôncio; Roatt, Bruno Mendes; Soares, Rodrigo Dian de Oliveira Aguiar; Marques, Marcos José; Veloso, Vanja Maria; Carneiro, MariângelaZoonotic visceral leishmaniasis in Brazil is caused by Leishmania infantum parasites andis transmitted by sand flies of the Phlebotominae family. Dogs are the main urban reser-voirs and represent the major source of contagion for the vectors. Studies have shown thatmost infected dogs are polymerase chain reaction-positive months before seroconversion.Herein, we describe a cohort study designed to identify the incidence of and risk factorsfor L. infantum infection as detected by polymerase chain reaction-restriction fragmentlength polymorphism. To determine the risk factors for infection, we conducted a base-line canine survey (n = 1443) from which dogs were selected for the cohort study (n = 282)involving three evaluations over the course of a 26-month follow-up period. Serology,molecular tests, and a structured questionnaire were used. The risk factors for infectionwere identified by means of the Cox regression model. The overall infection incidencewas 5.8 per 100 dog-months (95% confidence interval 5.1–6.5). Increased risk of infec-tion was associated with the presence of previous cases of canine visceral leishmaniasis inthe domiciles (hazard ratio [HR] 1.4; 95% confidence interval [CI] 1.1–1.8) and unplasteredhouse walls (HR 3.6; 95% CI 1.6–8.1). These risk factors suggest that insecticide spraying incracks and crevices in unplastered walls can reduce biting rates within and around homes.Furthermore, our results demonstrate that the Visceral Leishmaniasis Control and Surveil-lance Program should adopt environmental management measures in homes with previouscases of canine visceral leishmaniasis, because these homes are more likely to maintain thetransmission cycle.Item Canine visceral leishmaniasis biomarkers and their employment in vaccines.(2019) Giunchetti, Rodolfo Cordeiro; Silveira, Patricia; Resende, Lucilene Aparecida; Leite, Jaqueline Costa; Melo Júnior, Otoni Alves de Oliveira; Alves, Marina Luiza Rodrigues; Costa, Laís Moreira; Lair, Daniel Ferreira; Chaves, Vinícius Rossi; Soares, Ingrid dos Santos; Mendonça, Ludmila Zanandreis de; Lanna, Mariana Ferreira; Ribeiro, Helen Silva; Gonçalves, Ana Alice Maia; Santos, Thaiza Aline Pereira; Roatt, Bruno Mendes; Soares, Rodrigo Dian de Oliveira Aguiar; Souza, Juliana Vitoriano de; Moreira, Nádia das Dores; Siqueira, Fernando Augusto Mathias; Cardoso, Jamille Mirelle de Oliveira; Vital, Wendel Coura; Galdino, Alexsandro Sobreira; Viana, Kelvinson Fernandes; Martins Filho, Olindo Assis; Lemos, Denise da Silveira; Dutra, Walderez Ornelas; Reis, Alexandre BarbosaThe natural history of canine visceral leishmaniasis (CVL) has been well described, particularly with respect to the parasite load in different tissues and immunopathological changes according to the progression of clinical forms. The biomarkers evaluated in these studies provide support for the improvement of the tools used in developing vaccines against CVL. Thus, we describe the major studies using the dog model that supplies the rationale for including different biomarkers (tissue parasitism, histopathology, hematological changes, leucocytes immunophenotyping, cytokines patterns, and in vitro co-culture systems using purified T-cells subsets and macrophages infected with L. infantum) for immunogenicity and protection evaluations in phases I and II applied to pre-clinical and clinical vaccine trials against CVL. The search for biomarkers related to resistance or susceptibility has revealed a mixed cytokine profile with a prominent proinflammatory immune response as relevant for Leishmania replication at low levels as observed in asymptomatic dogs (highlighted by high levels of IFN-γ and TNF-α and decreased levels in IL-4, TGF-β and IL-10). Furthermore, increased levels in CD4+ and CD8+ T-cell subsets, presenting intracytoplasmic proinflammatory cytokine balance, have been associated with a resistance profile against CVL. In contrast, a polyclonal B-cell expansion towards plasma cell differentiation contributes to high antibody production, which is the hallmark of symptomatic dogs associated with high susceptibility in CVL. Finally, the different studies used to analyze biomarkers have been incorporated into vaccine immunogenicity and protection evaluations. Those biomarkers identified as resistance or susceptibility markers in CVL have been used to evaluate the vaccine performance against L. infantum in a kennel trial conducted before the field trial in an area known to be endemic for visceral leishmaniasis. This rationale has been a guiding force in the testing and selection of the best vaccine candidates against CVL and provides a way for the veterinary industry to register commercial immunobiological products.Item Cell immune response in mice skin stimulated with different adjuvants by intradermal route.(2022) Mathias, Fernando Augusto Siqueira; Cardoso, Jamille Mirelle de Oliveira; Reis, Levi Eduardo Soares; Souza, Juliana Vitoriano de; Moreira, Nádia das Dores; Ostolin, Thais Lopes Valentim Di Paschoale; Brito, Rory Cristiane Fortes de; Soares, Rodrigo Dian de Oliveira Aguiar; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Roatt, Bruno Mendes; Reis, Alexandre BarbosaAdjuvants act in the innate immunity and, when combined to vaccine antigens, can produce a more intense response, improving the antigen presentation, directing the immune system, excellent for new vaccine formulations. This study evaluated the use of the intradermal route and the immune response triggered by a single dose of the adjuvants Aluminum Hydroxide (Al(OH)3 ), Montanide Pet Gel A (MPGA), Glucopyranosyl Lipid A Stable Emulsion (GLA-SE), and Resiquimod (R-848) in the mice skin. As control mice received sterile saline. MPGA and GLA-SE led to cell recruitment when compared with control group, with intense presence of neutrophils in first 12 hours, replaced by macrophages after 168 hours. R-848 and Al(OH)3 showed similar cell recruitment profiles. Regarding cytokine production, groups that received MPGA and GLA-SE produced high levels of IL-6, TNF-α, and IFN-γ. R-848 and Al(OH)3 groups displayed similar profile of cytokine production only at the first hour. Our results suggest that the intradermal route is efficient inducing immune system activation and GLA-SE was promising adjuvants for a type 1 immune response vaccine.Item Cellular immunophenotypic profile in the splenic compartment during canine visceral leishmaniasis.(2014) Reis, Alexandre Barbosa; Carvalho, Andréa Teixeira de; Giunchetti, Rodolfo Cordeiro; Roatt, Bruno Mendes; Vital, Wendel Coura; Nicolato, Roney Luiz de Carvalho; Lemos, Denise da Silveira; Oliveira, Rodrigo Corrêa de; Martins Filho, Olindo AssisTo determine the role of the spleen in the pathogenesis of canine visceral leishmaniasis (CVL), we analyzed cellular immunophenotypic profiles of 52 dogs naturally infected with Leishmania infantum, clinically classified as follows: asymptomatic dogs-I (AD-I), seroneg-ative/PCR+; asymptomatic dogs-II (AD-II), seropositive/PCR+; oligosymptomatic dogs (OD) and symptomatic dogs (SD). Seven non-infected dogs (CD) were included as a control group. AD-II presented higher levels of CD8+ T splenocytes and lower TCD4+/TCD8+ ratio in com-parison with CD. OD and SD showed lower percentages of CD21+ as compared with AD-II. All seropositive dogs presented lower levels of CD45RA+ than CD. Regardless of the stimuli used, the proliferation index from splenocytes in vitro was inversely correlated with clini-cal status. After LSA stimulation, there was a higher percentage of specific CD8+ T in AD-II than CD and non-stimulated culture. In contrast, splenocytes from SD under in vitro LSA stimulation induced decreased MHC-II+ expression in comparison with all groups, and non-stimulated culture. In conclusion, the role of CD8+ T splenocytes seems to be important for an effective immunological response, a hallmark of asymptomatic CVL, whereas the pro-nounced loss of MHC-II expression upon LSA stimulation is a biomarker of symptomatic CVL.Item A chimeric vaccine combined with adjuvant system induces immunogenicity and protection against visceral leishmaniasis in BALB/c mice.(2021) Ostolin, Thais Lopes Valentim Di Paschoale; Gusmão, Miriã Rodrigues; Mathias, Fernando Augusto Siqueira; Cardoso, Jamille Mirelle de Oliveira; Roatt, Bruno Mendes; Soares, Rodrigo Dian de Oliveira Aguiar; Ruiz, Jeronimo Conceição; Resende, Daniela de Melo; Brito, Rory Cristiane Fortes de; Reis, Alexandre BarbosaIn Brazil, canine visceral leishmaniasis is an important public health problem due to its alarming growth. The high prevalence of infected dogs reinforces the need for a vaccine for use in prophylactic vaccination campaigns. In the present study, we evaluate the immunogenicity and protection of the best dose of Chimera A selected through the screening of cytokines production important in disease. BALB/c mice were vaccinated subcutaneously with three doses and challenged intravenously with 1 107 L. infantum promastigotes. Spleen samples were collected to assess the intracellular cytokine profile production, T cell proliferation and parasite load. At first, three different doses of Chimera A (5 lg, 10 lg and 20 lg) were evaluated through the production of IFN-c and IL-10 cytokines. Since the dose of 20 lg showed the best results, it was chosen to continue the study. Secondarily, Chimera A at dose of 20 lg was formulated with Saponin plus Monophosphoryl lipid A. Vaccination with Chimera A alone and formulated with SM adjuvant system was able to increase the percentage of the proliferation of specific T lymphocytes and stimulated a Th1 response with increased levels of IFN-c, TNF-a and IL-2, and decreased of IL-4 and IL-10. The vaccine efficacy through real-time PCR demonstrated a reduction in the splenic parasite load in animals that received Chimera A formulated with the SM adjuvant system (92%). Additionally, we observed increased levels of nitric oxide in stimulated-culture supernatants. The Chimera A formulated with the SM adjuvant system was potentially immunogenic, being able to induce immunoprotective mechanisms and reduce parasite load. Therefore, the use of T-cell multi-epitope vaccine is promising against visceral leishmaniasis.Item Chimeric vaccines designed by immunoinformatics-activated polyfunctional and memory T cells that trigger protection against experimental visceral leishmaniasis.(2020) Brito, Rory Cristiane Fortes de; Ruiz, Jeronimo Conceição; Cardoso, Jamille Mirelle de Oliveira; Ostolin, Thais Lopes Valentim Di Paschoale; Reis, Levi Eduardo Soares; Mathias, Fernando Augusto Siqueira; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno Mendes; Oliveira, Rodrigo Corrêa de; Resende, Daniela de Melo; Reis, Alexandre BarbosaMany vaccine candidates against visceral leishmaniasis (VL) have been proposed; however, to date, none of them have been efficacious for the human or canine disease. On this basis, the design of leishmaniasis vaccines has been constantly changing, and the use of approaches to select specific epitopes seems to be crucial in this scenario. The ability to predict T cell-specific epitopes makes immunoinformatics an even more necessary approach, as in VL an efficient immune response against the parasite is triggered by T lymphocytes in response to Leishmania spp. immunogenic antigens. Moreover, the success of vaccines depends on the capacity to generate long-lasting memory and polyfunctional cells that are able to eliminate the parasite. In this sense, our study used a combination of different approaches to develop potential chimera candidate vaccines against VL. The first point was to identify the most immunogenic epitopes of Leishmania infantum proteins and construct chimeras composed of Major histocompatibility complex (MHC) class I and II epitopes. For this, we used immunoinformatics features. Following this, we validated these chimeras in a murine model in a thorough memory study and multifunctionality of T cells that contribute to a better elucidation of the immunological protective mechanisms of polyepitope vaccines (chimera A and B) using multicolor flow cytometry. Our results showed that in silico-designed chimeras can elicit polyfunctional T cells producing T helper (Th)1 cytokines, a strong immune response against Leishmania antigen, and the generation of central and effector memory T cells in the spleen cells of vaccinated animals that was able to reduce the parasite burden in this organ. These findings contribute two potential candidate vaccines against VL that can be used in further studies, and help in this complex field of vaccine development against this challenging parasite.Item Clinical forms of canine visceral Leishmaniasis in naturally Leishmania infantum – infected dogs and related myelogram and hemogram changes.(2013) Nicolato, Roney Luiz de Carvalho; Abreu, Raquel Trópia de; Roatt, Bruno Mendes; Soares, Rodrigo Dian de Oliveira Aguiar; Reis, Levi Eduardo Soares; Carvalho, Maria das Graças; Carneiro, Cláudia Martins; Giunchetti, Rodolfo Cordeiro; Bouillet, Leoneide Érica Maduro; Lemos, Denise da Silveira; Vital, Wendel Coura; Reis, Alexandre BarbosaHematological analysis has limited applications for disease diagnosis in Leishmania infantum–infected dogs, but it can be very important in evaluating the clinical forms of the disease and in understanding the evolution of canine visceral leishmaniasis (CVL) pathogenesis. Recently, we demonstrated that alterations in leucopoiesis and erythropoiesis are related to clinical status and bone marrow parasite density in dogs naturally infected by L. infantum. To further characterize these alterations, we evaluated the association between the hematological parameters in bone marrow and peripheral blood alterations in groups of L. infantum–infected dogs: asymptomatic I (AD-I: serum negative/PCR+), asymptomatic II (AD-II: serum positive), oligosymptomatic (OD), and symptomatic (SD). Results were compared with those from noninfected dogs (NID). The SD group was found to present a decrease in erythropoietic lineage with concomitant reductions in erythrocytes, hemoglobin, and hematocrit parameters, resulting in anemia. The SD group also had increased neutrophils and precursors and decreased band eosinophils and eosinophils, leading to peripheral blood leucopenia. In the AD-II group, lymphocytosis occurred in both the peripheral blood and the bone marrow compartments. The SD group exhibited lymphocytosis in the bone marrow, with lymphopenia in the peripheral blood. In contrast, the AD-I group, showed no significant changes suggestive of CVL, presenting normal counts in bone marrow and peripheral blood. Our results showed for the first time that important changes in hematopoiesis and hematological parameters occur during ongoing CVL in naturally infected dogs, mainly in symptomatic disease. Taken together, our results based on myelogram and hemogram parameters enable better understanding of the pathogenesis of the anemia, lymphocytosis, and lymphopenia, as well as the leucopenia (eosinopenia and monocytopenia), that contribute to CVL prognosis.Item Clinical, hematological and biochemical alterations in hamster (Mesocricetus auratus) experimentally infected with Leishmania infantum through different routes of inoculation.(2016) Moreira, Nádia das Dores; Souza, Juliana Vitoriano de; Roatt, Bruno Mendes; Vieira, Paula Melo de Abreu; Vital, Wendel Coura; Cardoso, Jamille Mirelle de Oliveira; Rezende, Mariana Trevisan; Ker, Henrique Gama; Giunchetti, Rodolfo Cordeiro; Carneiro, Cláudia Martins; Reis, Alexandre BarbosaBackground: Leishmaniasis remains among the most important parasitic diseases in the developing world and visceral leishmaniasis (VL) is the most fatal. The hamster Mesocricetus auratus is a susceptible model for the characterization of the disease, since infection of hamsters with L. infantum reproduces the clinical and pathological features of human VL. In this context, it provides a unique opportunity to study VL in its active form. The main goal of this study was to evaluate the clinical, biochemical, and hematological changes in male hamsters infected through different routes and strains of L. infantum. Methods: In the current study, hamsters (Mesocricetus auratus) were infected with the L. infantum strains (WHO/MHOM/BR/74/PP75 and MCAN/BR/2008/OP46) by intradermal, intraperitoneal and intracardiac routes. The animals were monitored for a nine month follow-up period. Results: The hamsters showed clinical signs similar to those observed in classical canine and human symptomatic VL, including splenomegaly, severe weight loss, anemia, and leucopenia. Therefore the OP46 strain was more infective, clinical signs were more frequent and more exacerbated in IC group with 80 to 100 % of the animals showing splenomegaly, in the last month infection. Additionally, desquamation, hair loss and external mucocutaneous lesions and ulcers localized in the snout, accompanied by swelling of the paws in all animals, were observed. Consequently, the animals presented severe weight loss/cachexia, hunched posture, an inability to eat or drink, and non-responsiveness to external stimuli. Furthermore, regardless of strain, route of inoculum and time assessed, the animals showed renal and hepatic alterations, with increased serum levels of urea and creatinine as well as elevated serum levels of aspartate aminotransferase and alanine aminotransferase. Conclusions: These results strongly suggest that the inoculation through the intracardiac route resulted in a higher severity among infections, especially in the sixth and ninth month after infection via intracardiac, exhibited clinical manifestations and biochemical/hematological findings similar to human visceral leishmaniasis. Therefore, we suggest that this route must be preferentially used in experimental infections for pathogenesis studies of VL in the hamster model.Item A clioquinol-containing Pluronic ® F127 polymeric micelle system is effective in the treatment of visceral leishmaniasis in a murine model.(2020) Tavares, Grasiele de Sousa Vieira; Mendonça, Débora Vasconcelos Costa; Pereira, Isabela Amorim Gonçalves; Silva, João Augusto Oliveira da; Ramos, Fernanda Fonseca; Lage, Daniela Pagliara; Machado, Amanda Sanchez; Carvalho, Lívia Mendes; Reis, Thiago Alves Rosa dos; Melo, Luísa Helena Perin de; Carvalho, Ana Maria Ravena Severino; Ottoni, Flaviano Melo; Ribeiro, Fernanda Ludolf; Freitas, Camila Simões de; Bandeira, Raquel Soares; Silva, Alessandra M.; Chávez Fumagalli, Miguel Angel; Duarte, Mariana Costa; Souza, Daniel Menezes; Alves, Ricardo José; Roatt, Bruno Mendes; Coelho, Eduardo Antônio FerrazA clioquinol (ICHQ)-containing Pluronic F127 polymeric micelle system (ICHQ/Mic) was recently shown to be effective against Leishmania amazonensis infection in a murine model. In the present study, ICHQ/ Mic was tested against L. infantum infection. BALB/c mice (n = 12 per group) were infected with L. infantum stationary promastigotes through subcutaneous injection and, 45 days after challenge, received saline or were treated via the subcutaneous route with empty micelles, ICHQ or ICHQ/Mic. In addition, animals were treated with miltefosine by the oral route, as a drug control. Half of the animals were euthanized 1 and 15 days after treatment, aiming to evaluate two endpoints after therapy, when parasitological and immunological parameters were investigated. Results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significantly higher anti-parasite IFN-c, IL-12, GM-CSF, nitrite and IgG2a isotype antibody levels, which were associated with low IL-4 and IL-10 production. In addition, a higher frequency of IFN-c and TNF-a-producing CD4+ and CD8+ T-cells was found in these animals. The parasite load was evaluated in distinct organs, and results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significant reductions in organic parasitism in the treated and infected mice. A comparison between the treatments suggested that ICHQ/Mic was the most effective in inducing a highly polarized Th1-type response, as well as reducing the parasite load in significant levels in the treated and infected animals. Data obtained 15 days after treatment suggested maintenance of the immunological and parasitological responses. In conclusion, ICHQ/Mic could be considered in future studies for the treatment of visceral leishmaniasis.Item Comparative analysis of real-time PCR assays in the detection of canine visceral leishmaniasis.(2018) Nunes, Juliana Barbosa; Vital, Wendel Coura; Colombo, Fabio Antonio; Baêta, Frederico José Moreira; Pinheiro, Aimara da Costa; Roatt, Bruno Mendes; Reis, Levi Eduardo Soares; Reis, Alexandre Barbosa; Marques, Marcos JoséDogs are important hosts and reservoirs of leishmaniasis, a disease caused by protozoan parasites from the genus Leishmania, affecting ~12 million people worldwide. The detection of visceral leishmaniasis (VL) in dogs by real-time PCR (qPCR) may improve on diagnosis, but the different qPCR methods available for Leishmania DNA detection have not been established as routine in diagnostic tools and/or epidemiologic studies for canine VL. Here, we compared three qPCR assays (DNApol, Linj31, and LDON) in the detection of VL by Leishmania infantum in spleen (n = 48; 7), skin (n = 48; 7), and whole blood (n = 44; 7) samples from serologically positive and negative dogs, respectively. Overall, the DNApol performed better than the Linj31 and LDON assays in the detection of positive samples in all tissues tested, yielding from 66.7 to 100.0% of positivity for both skin and spleen samples. For spleen samples, we observed no statistically significant differences between positive detection by the LDON and DNApol assays. Whole blood samples yielded the lowest rates of positive detection, regardless of the qPCR assay used. In contrast, positive detection of Leishmania DNA was as efficient from skin samples using the DNApol assay as from spleen samples using either the DNApol or the LDON assay. Although qPCR assays from skin samples may not be practical for use in the field, our study suggests that the DNApol and LDON assays from skin samples could be used in future to evaluate canine VL treatment in veterinary clinics.Item Comparative evaluation of meglumine antimoniate encapsulated in a mixture of conventional and PEGylated liposomes and immunotherapy using an anti-canine IL-10 receptor-blocking monoclonal antibody on canine visceral leishmaniasis.(2022) Cardoso, Jamille Mirelle de Oliveira; Brito, Rory Cristiane Fortes de; Mathias, Fernando Augusto Siqueira; Reis, Levi Eduardo Soares; Vieira, João Filipe Pereira; Ostolin, Thais Lopes Valentim Di Paschoale; Andrade, Hélida Monteiro de; Ramos, Guilherme Santos; Frezard, Frederic; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno Mendes; Reis, Alexandre BarbosaThis study compared the therapeutic potential of the chemotherapy using meglumine antimoniate encapsulated in a mixture of conventional and PEGylated liposomes (Nano Sbv ) and immunotherapy with anti-canine IL-10 receptor-blocking monoclonal antibody (Anti IL-10R) on canine visceral leishmaniasis (CVL). Twenty mongrel dogs naturally infected by L. infantum, displaying clinical signs of visceral leishmaniasis were randomly divided in two groups. In the first one, nine dogs received six intravenous doses of a mixture of conventional and PEGylated liposomes containing meglumine antimoniate at 6.5 mg Sb/kg/dose. In the second one, eleven dogs received two intramuscular doses of 4 mg of anti-canine IL-10 receptor-blocking monoclonal antibody. The animals were evaluated before (T0) and 30, 90, and 180 days after treatments. Our major results demonstrated that both treatments were able to maintain hematological and biochemical parameters, increase circulating T lymphocytes subpopulations, increase the IFN-γ producing T-CD4 lymphocytes, restore the lymphoproliferative capacity and improve the clinical status. However, although these improvements were observed in the initial post-treatment times, they did not maintain until the end of the experimental follow-up. We believe that the use of booster doses or the association of chemotherapy and immunotherapy (immunochemotherapy) is promising to improve the effectiveness of treating CVL for improving the clinical signs and possibly reducing the parasite burden in dogs infected with Leishmania infantum.Item Comparative genomics of canine-isolated Leishmania (Leishmania) amazonensis from an endemic focus of visceral leishmaniasis in Governador Valadares, southeastern Brazil.(2017) Valdivia Rodríguez, Hugo Oswaldo; Almeida, Laila Viana de; Roatt, Bruno Mendes; Cunha, João Luís Reis; Pereira, Agnes Antônia Sampaio; Gontijo, Célia Maria Ferreira; Fujiwara, Ricardo Toshio; Reis, Alexandre Barbosa; Sanders, Mandy J.; Cotton, James A.; Bartholomeu, Daniella CastanheiraLeishmaniasis is a highly diverse group of diseases caused by kinetoplastid of the genus Leishmania. These parasites are taxonomically diverse, with human pathogenic species separated into two subgenera according to their development site inside the alimentary tract of the sand fly insect vector. The disease encompasses a variable spectrum of clinical manifestations with tegumentary or visceral symptoms. Among the causative species in Brazil, Leishmania (Leishmania) amazonensis is an important etiological agent of human cutaneous leishmaniasis that accounts for more than 8% of all cases in endemic regions. L. (L.) amazonensis is generally found in the north and northeast regions of Brazil. Here, we report the first isolation of L. (L.) amazonensis from dogs with clinical manifestations of visceral leishmaniasis in Governador Valadares, an endemic focus in the southeastern Brazilian State of Minas Gerais where L. (L.) infantum is also endemic. These isolates were characterized in terms of SNPs, chromosome and gene copy number variations, confirming that they are closely related to a previously sequenced isolate obtained in 1973 from the typical Northern range of this species. The results presented in this article will increase our knowledge of L. (L.) amazonensis-specific adaptations to infection, parasite survival and the transmission of this Amazonian species in a new endemic area of Brazil.