Effect of Therapy on Paracoccidioidomicotic Granuloma Modulation.

A paracoccidioidomicose é uma micose sistêmica caracterizada por ser uma doença granulomatosa. As formas benignas da doença são caracterizadas por uma infecção localizada, contendo granulomas compactos com poucos fungos; já nas formas mais graves, ocorre um processo granulomatoso frouxo com focos de necrose e intensa disseminação fúngica. Objetivou-se avaliar o desenvolvimento de lesões granulomatosas em baço, fígado, pulmão e epiplon de camundongos, após infecção pela via intraperitoneal com o isolado de alta virulência, Pb18, em diferentes períodos de infecção após tratamento com fármacos, os quais possuem mecanismo de ação relacionado com a alteração no balanço entre a síntese e degradação dos produtos do colágeno, interferindo diretamente na formação do granuloma A citocina IFN-g, o antibiótico Tetraciclina e as drogas antiinflamatórias Lumiracoxib e Celecoxib. Avaliamos a presença de alguns componentes do granuloma (colágeno, células do infiltrado inflamatório, de citocinas primordiais para sintese/degradação da MEC do granuloma, presença de P. brasiliensis).Paracoccidioidomycosis (PCM) is a systemic mycosis that is endemic in Latin America, whose causative agent is the thermal dimorphic fungus Paracoccidioides brasiliensis (Pb). PCM is a granulomatous disease, and the formation of granulomas can be understood as a mechanism of the body to block and limit the invasiveness of the fungus or its antigenic components, once unable to lyse them. Bening forms of the disease are characterized by a localized infection, where granulomasa are compact and contain few fungi. More severe forms present loose granulomatous processes with foci of necrosis and severe fungal. Studies in which granulomatous response was developed in resistant (A/J) and susceptible (B10.A) mice to the high virulence isolate Pb18 showed the presence of different patterns of injuries related to the type of extracellular matrix (ECM) components and the different cells types in the area, suggesting a important role of these elements in the formation and constitution of the granuloma and thus the outcome of infection. In our project, we aimed to evaluate the development of granulomatous lesions in the spleen, liver, lung and omentum of mice susceptible to PCM after intraperitoneal infection with Pb18, at different periods of infection (acute and chronic) with or without treatment with drugs. These drugs have mechanisms of action closely related to the change in the balance between synthesis and degradation of collagen Thus, they interfere directly in the granuloma formation and in maintaining the viability of fungi and also with the development of fibrosis. Which is a common and devastating sequelae of numerous infections including the PCM, with the characteristic proliferation of fibroblasts and deposition of ECM. The treatments were chosen based on prior knowledge on their effects on the course of experimental murine PCM. IFN-g was chosen due to its antifibrotic effect, being an activator of macrophages in infection by P. brasiliensis and increasing the fungicidal effect of neutrophils. The antibiotic tetracycline was used because of its inhibitory effect on the synthesis of extracellular matrix, limiting antimicrobial activity and the ability of collagenase to degrade ECM. Finally, the antiinflammatory drugs Celecoxib and Lumiracoxib (inhibitors of the COX-2 enzyme) 11 were used because they cause an increase in the expression of collagen type III and type IV. We analyzed the components of the granuloma (collagen, inflammatory cells, cytokines essential for synthesis / degradation of the ECM of the granuloma, the presence of P. brasiliensis). Among the cytokines analyzed, we studied the importance of TNF-&#945 in the formation of granulomas and regulation of matrix metalloproteinases (MMP) synthesis and function. We analyzed TGF-b because it negatively modulate the secretion of nitric oxide by macrophages and promote the accumulation of ECM and is believed to be the central mediator of the process of fibrosis in several pathologies. IFN-g was studied because of its correlation to the preferential Th1 immune response in diseases and infectious processes of fungal and bacterial infections, and also because it modulates fibroblast function

Nitric oxide participation in granulomatous response induced by Paracoccidioides brasiliensis infection in mice

The role of nitric oxide (NO) in granulomas of Paracoccidioides brasiliensis-infected inducible NO synthase-deficient C57BL/6 mice (iNOS KO) and their wild-type counterparts and its association with osteopontin (OPN) and matrix metalloproteinases (MMPs) was studied. At 15 days after infection (DAI), iNOS KO mice showed compact and necrotic granulomas with OPN+ macrophages and multinucleated giant cells, whereas wild-type mice developed loose granulomas with many fungi and OPN+ cells distributed throughout the tissue. In addition, high OPN levels and fungal load were observed in iNOS KO mice. Both experimental groups had MMP-9 activity. At 120 DAI, iNOS KO had smaller granulomas with OPN+ cells, lower OPN levels, lower fungal load and decreased MMP-9 activity compared with wild-type mice. These findings suggest that NO has an important role in granuloma modulation, by controlling OPN and MMP production, as well as by inducing loose granulomas formation and fungal dissemination, resulting, at later phases, in progression of paracoccidioidomycosis