Navegando por Autor "Coelho, Vinicio Tadeu da Silva"
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Item A chloroquinoline derivate presents effective in vitro and in vivo antileishmanial activity against Leishmania species that cause tegumentary and visceral leishmaniasis.(2019) Sousa, Jéssica Karine Távora de; Antinarelli, Luciana Maria Ribeiro; Mendonça, Débora Vasconcelos Costa; Lage, Daniela Pagliara; Tavares, Grasiele de Sousa Vieira; Dias, Daniel Silva; Ribeiro, Patrícia Aparecida Fernandes; Ribeiro, Fernanda Ludolf; Coelho, Vinicio Tadeu da Silva; Silva, João Augusto Oliveira da; Melo, Luísa Helena Perin de; Oliveira, Bianka A.; Alvarenga, Denis Fernando; Chávez Fumagalli, Miguel Angel; Brandão, Geraldo Célio; Vandack, Nobre; Pereira, Guilherme Rocha; Coimbra, Elaine Soares; Coelho, Eduardo Antônio FerrazThe identification of new therapeutics to treat leishmaniasis is desirable, since available drugs are toxic and present high cost and/or poor availability. Therefore, the discovery of safer, more effective and selective pharmaceutical options is of utmost importance. Efforts towards the development of new candidates based on molecule analogs with known biological functions have been an interesting and cost-effective strategy. In this context, quinoline derivatives have proven to be effective biological activities against distinct diseases. In the present study, a new chloroquinoline derivate, AM1009, was in vitro tested against two Leishmania species that cause leishmaniasis. The present study analyzed the necessary inhibitory concentration to preclude 50% of the Leishmania promastigotes and axenic amastigotes (EC50 value), as well as the inhibitory concentrations to preclude 50% of the murine macrophages and human red blood cells (CC50 and RBC50 values, respectively). In addition, the treatment of infected macrophages and the inhibition of infection using pre-treated parasites were also investigated, as was the mechanism of action of the molecule in L. amazonensis. To investigate the in vivo therapeutic effect, BALB/c mice were infected with L. amazonensis and later treated with AM1009. Parasitological and immunological parameters were also evaluated. Clioquinol, a known antileishmanial quinoline derivate, and amphotericin B (AmpB), were used as molecule and drug controls, respectively. Results in both in vitro and in vivo experiments showed a better and more selective action of AM1009 to kill the in vitro parasites, as well as in treating infected mice, when compared to results obtained using clioquinol or AmpB. AM1009-treated animals presented significantly lower average lesion diameter and parasite burden in the infected tissue and organs evaluated in this study, as well as a more polarized antileishmanial Th1 immune response and low renal and hepatic toxicity. This result suggests that AM1009 should be considered a possible therapeutic target to be evaluated in future studies for treatment against leishmaniasis.Item Digitoxigenin presents an effective and selective antileishmanial action against Leishmania infantum and is a potential therapeutic agent for visceral leishmaniasis.(2020) Freitas, Camila Simões de; Silva, João Augusto Oliveira da; Lage, Daniela Pagliara; Costa, Rafaella Rodrigues; Mendonça, Débora Vasconcelos Costa; Martins, Vívian Tamietti; Reis, Thiago Alves Rosa dos; Antinarelli, Luciana Maria Ribeiro; Machado, Amanda Sanchez; Tavares, Grasiele de Sousa Vieira; Ramos, Fernanda Fonseca; Coelho, Vinicio Tadeu da Silva; Brito, Rory Cristiane Fortes de; Ribeiro, Fernanda Ludolf; Chávez Fumagalli, Miguel Angel; Roatt, Bruno Mendes; Ramos, Gabriela S.; Munkert, Jennifer; Ottoni, Flaviano Melo; Campana, Priscilla Rodrigues Valadares; Humbert, Maria Victoria; Coimbra, Elaine Soares; Braga, Fernão Castro; Pádua, Rodrigo Maia de; Coelho, Eduardo Antônio FerrazTreatment for visceral leishmaniasis (VL) is hampered mainly by drug toxicity, their high cost, and parasite resistance. Drug development is a long and pricey process, and therefore, drug repositioning may be an alternative worth pursuing. Cardenolides are used to treat cardiac diseases, especially those obtained from Digitalis species. In the present study, cardenolide digitoxigenin (DIGI) obtained from a methanolic extract of Digitalis lanata leaves was tested for its antileishmanial activity against Leishmania infantum species. Results showed that 50% Leishmania and murine macrophage inhibitory concentrations (IC50 and CC50, respectively) were of 6.9 ± 1.5 and 295.3 ± 14.5 μg/mL, respectively. With amphotericin B (AmpB) deoxycholate, used as a control drug, values of 0.13 ± 0.02 and 0.79 ± 0.12 μg/mL, respectively, were observed. Selectivity index (SI) values were of 42.8 and 6.1 for DIGI and AmpB, respectively. Preliminary studies suggested that the mechanism of action for DIGI is to cause alterations in the mitochondrial membrane potential, to increase the levels of reactive oxygen species and induce accumulation of lipid bodies in the parasites. DIGI was incorporated into Pluronic® F127-based polymeric micelles, and the formula (DIGI/Mic) was used to treat L. infantum–infected mice. Miltefosine was used as a control drug. Results showed that animals treated with either miltefosine, DIGI, or DIGI/Mic presented significant reductions in the parasite load in their spleens, livers, bone marrows, and draining lymph nodes, as well as the development of a specific Th1-type response, when compared with the controls. Results obtained 1 day after treatment were corroborated with data corresponding to 15 days after therapy. Importantly, treatment with DIGI/Mic induced better parasitological and immunological responses when compared with miltefosine- and DIGI-treated mice. In conclusion, DIGI/Mic has the potential to be used as a therapeutic agent to protect against L. infantum infection, and it is therefore worth of consideration in future studies addressing VL treatment.