Browsing by Author "Maioli, Tatiani Uceli"

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    Consumption of conjugated linoleic acid (CLA)-supplemented diet during colitis development ameliorates gut inflammation without causing steatosis in mice.
    (2018) Moreira, Thais Garcias; Santos, Ana Cristina Gomes; Horta, Laila Sampaio; Miranda, Mariana Camila Gonçalves; Santiago, Andrezza Fernanda; Gonçalves, Juliana Lauar; Reis, Daniela Silva dos; Castro Junior, Archimedes Barbosa de; Santos, Luísa Lemos dos; Guimarães, Mauro Andrade de Freitas; Aguilar, Edenil Costa; Pap, Attila; Amaral, Joana Ferreira do; Leite, Jacqueline Isaura Alvarez; Machado, Denise Carmona Cara; Rezende, Rafael Machado; Nagy, Laszlo; Faria, Ana Maria Caetano de; Maioli, Tatiani Uceli
    Dietary supplementation with conjugated linoleic acid (CLA) has been proposed for weight management and to prevent gut inflammation. However, some animal studies suggest that supplementation with CLA leads to the development of nonalcoholic fatty liver disease. The aims of this study were to test the efficiency of CLA in preventing dextran sulfate sodium (DSS)-induced colitis, to analyze the effects of CLA in the liver function, and to access putative liver alterations upon CLA supplementation during colitis. So, C57BL/6 mice were supplemented for 3 weeks with either control diet (AIN-G) or 1% CLA-supplemented diet. CLA content in the diet and in the liver of mice fed CLA containing diet were accessed by gas chromatography. On the first day of the third week of dietary treatment, mice received ad libitum a 1.5%–2.5% DSS solution for 7 days. Disease activity index score was evaluated; colon and liver samples were stained by hematoxylin and eosin for histopathology analysis and lamina propria cells were extracted to access the profile of innate cell infiltrate. Metabolic alterations before and after colitis induction were accessed by an open calorimetric circuit. Serum glucose, cholesterol, triglycerides and alanine aminotransaminase were measured; the content of fat in liver and feces was also accessed. CLA prevented weight loss, histopathologic and macroscopic signs of colitis, and inflammatory infiltration. Mice fed CLA-supplemented without colitis induction diet developed steatosis, which was prevented in mice with colitis probably due to the higher lipid consumption as energy during gut inflammation. This result suggests that CLA is safe for use during gut inflammation but not at steady-state conditions.
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    Efeito da administração diária de cafeína sobre a infecção por Leishmania amazonensis.
    (2017) Carvalho Júnior, Jaime Márcio de; Afonso, Luís Carlos Crocco; Testasicca, Miriam Conceição de Souza; Afonso, Luís Carlos Crocco; Bahia, Maria Terezinha; Maioli, Tatiani Uceli
    A leishmaniose pode ser descrita como um conjunto de manifestações clínicas causadas pela infecção de protozoários do gênero Leishmania. Essas manifestações clínicas podem ser agrupadas em quatro quadros bem definidos: leishmaniose cutânea localizada, leishmaniose muco-cutânea, leishmaniose visceral e leishmaniose cutânea difusa. As diferentes condições dependerão de fatores inerentes ao hospedeiro humano e por características do parasito. Por exemplo, L. amazonensis é o único causador da leishmaniose cutânea difusa. Para essa condição clínica o balanço das citocinas produzidas pelas células T CD4 positivas é de grande importância. A infecção por L. amazonensis resulta no desenvolvimento de uma fraca resposta celular T CD4 Th1 em pacientes que são negativos para a reação de hipersensibilidade a antígenos de Leishmania. A deficiência na resposta celular pode ser consequência de mecanismos de evasão específicos de L. amazonensis que podem induzir imunossupressão no hospedeiro. A presença de ectonucleotidases e produção de adenosina extracelular pode representar um desses mecanismos. Atuando nesses receptores, a adenosina pode induzir respostas antiinflamatórias, o que favorece a multiplicação do parasito. Sendo a cafeína por sua vez, uma metilxantina capaz de antagonizar os efeitos da adenosina nos receptores P1, nosso objetivo foi investigar os efeitos da administração diária de cafeína sobre a infecção por L. amazonensis no modelo murino. Camundongos C57BL/6J foram tratados com diferentes concentrações de cafeína em água de beber e posteriormente infectados com metacíclicas de L. amazonensis. Os animais tratados com cafeína apresentaram menor tamanho de lesão quando comparados com os animais não tratados e não observamos diferença no número de parasitos na lesão. A produção de IFN-ɣ por células do linfonodo foi significativamente maior nos animais tratados com cafeína. Concluímos, portanto, que o tratamento com cafeína possuiu a capacidade de interferir no curso da infecção por L. amazonensis. Essa interferência pode ser explicada pela alteração na produção de citocinas como o IFN-ɣ. Dessa maneira o tratamento com cafeína pode oferecer mais um meio de expandir os conhecimentos a respeito dos mecanismos de evasão da resposta imune utilizados pelo parasito, através da sinalização purinérgica, e melhorando o entendimento do papel desta via no curso da infecção por L. amazonensis.
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    Immune response induced by New World Leishmania species in C57BL/6 mice.
    (2004) Maioli, Tatiani Uceli; Takane, Erica; Arantes, Rosa Maria Esteves; Fietto, Juliana Lopes Rangel; Afonso, Luís Carlos Crocco
    In the present study, C57BL/6 mice were inoculated with metacyclic Leishmania amazonensis or L. braziliensis promastigotes. While these animals were capable of controlling the infection by L. braziliensis, they developed chronic lesions with elevated numbers of parasites when infected by L. amazonensis. The differences in parasite control were associated with a decreased production of IFN-c and TNF by lymph node cells from L. amazonensis-infected mice. Furthermore, these animals presented decreased spleen cell proliferation and activation of germinal centers. In addition, we compared the ability of these parasites to hydrolyze extracellular ATP and AMP. While the ATPase activity of both parasite species was similar, L. amazonensis promastigotes presented higher AMP hydrolytic activity. This increased activity may lead to an increased production of adenosine, which has been shown to present anti-inflammatory activity and may thus be involved in the establishment of the immunosuppression observed in mice infected by L. amazonensis.
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    Low and high-dose intradermal infection with Leishmania major and Leishmania amazonensis in C57BL/6 mice.
    (2010) Côrtes, Denise Fonseca; Carneiro, Matheus Batista Heitor; Santos, Liliane Martins dos; Souza, Talita Correia de Oliveira; Maioli, Tatiani Uceli; Duz, Ana Luiza Cassin; Jorge, Maria Letícia Ramos; Afonso, Luís Carlos Crocco; Carneiro, Cláudia Martins; Vieira, Leda Quercia
    A model of skin infection with Leishmania amazonensis with low doses of parasites is compared to infection with high doses of L. amazonensis and low and high doses of Leishmania major. C57BL/6 mice were infected with 103 or 106 parasites in the ear and the outcome of infection was assessed. The appearance of lesions in mice infected with 103 parasites was delayed compared to mice infected with 106 Leishmania and parasites were detectable at the infection site before lesions became apparent. Mice infected with L. amazonensis displayed persistent lesions, whereas infection with L. major spontaneously healed in all groups, although lymphocytes persisted at the site of infection after healing. Macrophages persisted only in L. amazonensis-infected mice. High-dose L. amazonensis-infected mice produced lower levels of IFN-γ and TNF than mice infected with L. major. No correlation between the persistence of parasites and IL-10 levels and the production of nitric oxide or urea by macrophages was found. We conclude that infection with low doses of L. amazonensis in the dermis changes the course of infection by delaying the appearance of lesions. However, low-dose infection does not change the outcomes of susceptibility and cytokine production described for subcutaneous infection with high numbers of parasites.
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    Obesity impairs resistance to Leishmania major infection in C57BL/6 mice.
    (2020) Martins, Vinicius Dantas; Campos, Franciele Carolina Silva; Moreira, Felipe Caixeta; Carneiro, Matheus Batista Heitor; Goes, Grazielle Ribeiro; Torres, Lícia; Barbosa, Sara Cândida; Vaz, Leonardo Gomes; Paiva, Nívia Carolina Nogueira de; Carneiro, Cláudia Martins; Vieira, Leda Quercia; Faria, Ana Maria Caetano de; Maioli, Tatiani Uceli
    An association between increased susceptibility to infectious diseases and obesity has been described as a result of impaired immunity in obese individuals. It is not clear whether a similar linkage can be drawn between obesity and parasitic diseases. To evaluate the effect of obesity in the immune response to cutaneous Leishmania major infection, we studied the ability of C57BL/6 mice fed a hypercaloric diet (HSB) to control leishmaniasis. Mice with diet-induced obesity presented thicker lesions with higher parasite burden and a more intense inflammatory infiltrate in the infected ear after infection with L. major. There was no difference between control and obese mice in IFN-gamma or IL-4 production by auricular draining lymph node cells, but obese mice produced higher levels of IgG1 and IL-17. Peritoneal macrophages from obese mice were less efficient to kill L. major when infected in vitro than macrophages from control mice. In vitro stimulation of macrophages with IL-17 decreased their capacity to kill the parasite. Moreover, macrophages from obese mice presented higher arginase activity. To confirm the role of IL-17 in the context of obesity and infection, we studied lesion development in obese IL-17R-/- mice infected with L. major and found no difference in skin lesions and the leukocyte accumulation in the draining lymph node is redcuced in knockout mice compared between obese and lean animals. Our results indicate that diet-induced obesity impairs resistance to L. major in C57BL/6 mice and that IL-17 is involved in lesion development.
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    Splenectomy does not interfere with immune response to Leishmania major infection in mice.
    (2007) Maioli, Tatiani Uceli; Carneiro, Cláudia Martins; Assis, Frankcinéia Aparecida de; Faria, Ana Maria Caetano de
    Spleen is one of the largest lymphoid organs in the body; it harbors immune cells including antigen presenting cells, B and T lymphocytes. It has an important role in humoral and cellular immune responses. Herein we investigated the role of spleen in the immune response to experimental Leishmania major infection. It is known that C57BL/6 mice are resistant to L. major infection whereas BALB/c mice are susceptible. Although splenectomy was associated with reduced serum levels of IFN-gamma, absence of the spleen did not change the profile of L. major infection in the resistant C57BL/6 and BALB/c susceptible mice. Both strains of mice maintained the same profile of cytokine production in regional lymph nodes after splenectomy and responded in the same way against the infection. Only splenectomized BALB/c mice had a reduction in IL-4 and IL-10 production by lymph node cells early in infection. Our data suggest that, in localized infections, regional lymph nodes may replace efficiently the immunological role of spleen in the cellular and humoral immune responses.
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    Splenectomy increases mortality in murine Trypanosoma cruzi infection.
    (2011) Maioli, Tatiani Uceli; Assis, Frankcinéia Aparecida de; Vieira, Paula Melo de Abreu; Borelli, Primavera; Santiago, Helton da Costa; Alves, Ricardo José; Romanha, Alvaro José; Carneiro, Cláudia Martins; Faria, Ana Maria Caetano de
    The spleen is a secondary lymphoid organ that harbours a variety of cells such as T and B lymphocytes and antigen-presenting cells important to immune response development. In this study, we evaluated the impact of spleen removal in the immune response to experimental Trypanosoma cruzi infection. C57BL/6 mice were infected with Y strain of the parasite and infection was followed daily. Mice that underwent splenectomy had fewer parasites in peripheral blood at the peak of infection; however, mortality was increased. Histological analysis of heart and liver tissues revealed an increased number of parasites and inflammatory infiltrates at these sites. Spleen removal was associated with reduction in IFN-γ and TNF-α production during infection as well as with a decrease in specific antibody secretion. Haematological disorders were also detected. Splenectomized mice exhibited severe anaemia and decreased bone marrow cell numbers. Our results indicate that spleen integrity is critical in T. cruzi infection for the immune response against the parasite, as well as for the control of bone marrow haematological function.