Browsing by Author "Mariano, Reysla Maria da Silveira"

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    In vitro Infectivity of strains isolated from dogs naturally infected with Leishmania infantum present a distinct pathogenic profile in hamsters.
    (2020) Resende, Lucilene Aparecida; Soares, Rodrigo Dian de Oliveira Aguiar; Moreira, Nádia das Dores; Ferreira, Sidney de Almeida; Lanna, Mariana Ferreira; Cardoso, Jamille Mirelle de Oliveira; Mathias, Fernando Augusto Siqueira; Vital, Wendel Coura; Mariano, Reysla Maria da Silveira; Leite, Jaqueline Costa; Silveira, Patricia; Carvalho, Tatiane Furtado de; Santos, Renato Lima; Lemos, Denise da Silveira; Martins Filho, Olindo Assis; Dutra, Walderez Ornelas; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro
    Visceral leishmaniasis (VL) is a severe disease caused by Leishmania infantum. Dogs are the parasite’s main reservoir, favoring its transmission in the urban environment. The analysis of L. infantum from infected dogs contributes to the identification of more virulent parasites, thereby supporting basic and applied studies such as vaccinal and therapeutic strategies. We proposed the in vitro and in vivo characterization of L. infantum strains from naturally infected dogs from a VL endemic area based on an infectivity and pathogenicity analysis. DH82 canine macrophages were infected in vitro with different strains for infectivity analysis, showing distinct infectivity profiles. The strains that showed greater and lesser infectivity using in vitro analyses (616 and 614, respectively) were used to infect hamsters for pathogenicity analysis. The group infected with strain 616 showed 100% survival while the group infected with strain 614 showed 50% after seven months of follow up. Furthermore, the 614 strain induced more noticeable clinicopathological changes and biochemical abnormalities in liver function, along with high inflammation and parasite load in the liver and spleen. We confirmed high variability of infectivity and pathogenicity in L. infantum strains from infected dogs. The results support the belief that screening for L. infantum infectivity using in vitro experiments is inadequate when it comes to selecting the most pathogenic strain.
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    Kinetics of phenotypic and functional changes in mouse models of sponge implants : rational selection to optimize protocols for specific biomolecules screening purposes.
    (2020) Lanna, Mariana Ferreira; Resende, Lucilene Aparecida; Soares, Rodrigo Dian de Oliveira Aguiar; Miranda, Marina Barcelos de; Mendonça, Ludmila Zanandreis de; Melo Júnior, Otoni Alves de Oliveira; Mariano, Reysla Maria da Silveira; Leite, Jaqueline Costa; Silveira, Patricia; Oliveira, Rodrigo Corrêa de; Dutra, Walderez Ornelas; Reis, Alexandre Barbosa; Martins Filho, Olindo Assis; Moura, Sandra Aparecida Lima de; Lemos, Denise da Silveira; Giunchetti, Rodolfo Cordeiro
    The sponge implant has been applied as an important in vivo model for the study of inflammatory processes as it induces the migration, proliferation, and accumulation of inflammatory cells, angiogenesis, and extracellular matrix deposition in its trabeculae. The characterization of immune events in sponge implants would be useful in identifying the immunological events that could support the selection of an appropriate experimental model (mouse strain) and time post-implant analysis in optimized protocols for novel applications of this model such as in biomolecules screening. Here, the changes in histological/morphometric, immunophenotypic and functional features of infiltrating leukocytes (LEU) were assessed in sponge implants for Swiss, BALB/c, and C57BL/6 mice. A gradual increase of fibrovascular stroma and a progressive decrease in LEU infiltration, mainly composed of polymorphonuclear cells with progressive shift toward mononuclear cells at late time-points were observed over time. Usually, Swiss mice presented a more prominent immune response with late mixed pattern (pro-inflammatory/anti-inflammatory: IL-2/IFN-γ/IL-4/IL-10/IL-17) of cytokine production. While BALB/c mice showed an early activation of the innate response with a controlled cytokine profile (low inflammatory potential), C57BL/6 mice presented a typical early pro-inflammatory (IL-6/TNF/IFN-γ) response with persistent neutrophilic involvement. A rational selection of the ideal time-point/mouse-lineage would avoid bias or tendentious results. Criteria such as low number of increased biomarkers, no recruitment of cytotoxic response, minor cytokine production, and lower biomarker connectivity (described as biomarker signature analysis and network analysis) guided the choice of the best time-point for each model (Day5/Swiss; Day7/BALB/c; Day6/C57BL/6) with wide application for screening purposes, such as identification of therapeutic biomolecules, selection of antigens/adjuvants, and follow-up of innate and adaptive immune response to vaccines candidates.