Estudo do eixo intestino-rim: as alterações na microbiota intestinal em modelo experimental de glomeruloesclerose segmentar e focal
Data
2022-10-18
Autores
Silva, Denis Gonçalves 
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O dano na barreira intestinal contribui para a patogênese da inflamação sistêmica e progressão de muitas doenças humanas, incluindo a doença renal. De fato, o eixo microbiota-intestino-rim vem ganhando força como um possível mecanismo na fisiopatologia das doenças renais. No entanto, a maioria dos estudos se concentram nas alterações da microbiota intestinal e seus metabólitos em doenças renais crônicas, deixando de lado as doenças glomerulares/podocitárias em estágios iniciais, como na glomeruloesclerose segmentar focal (GESF). Neste estudo, exploramos a inter-relação entre a disfunção glomerular renal, as possíveis alterações na microbiota e no microambiente intestinal. Camundongos Balb/c machos foram submetidos ao protocolo de depleção de microbiota por 14 dias. Em seguida, foram induzidos quimicamente a desenvolver GESF por Doxorrubicina (DOX) e avaliados por mais 14 dias. Em outro experimento, sem a prévia depleção de microbiota, camundongos foram induzidos quimicamente a desenvolver glomerulopatia e foram avaliados por 30 dias. A DOX causou lesões histopatológicas renais, com diminuição do número de podócitos por glomérulo, disfunção da barreira glomerular e proteinúria, além de uma progressão, após 30 dias, para uremia. Por outro lado, os camundongos que tiveram sua microbiota intestinal previamente depletada exibiram melhor função da barreira glomerular com a indução da glomerulopatia, com níveis mais baixos de proteinúria e sem alterações estruturais no rim. Além disso, a depleção da microbiota intestinal alterou a relação Th1/Th2 no tecido renal após a glomerulopatia, principalmente pela redução de TNF e MCP-1 e pelo aumento de IL-6. Interessante, após 30 dias, o dano glomerular foi associado a alterações histológicas no cólon intestinal, com níveis aumentados de massa celular amorfa e níveis diminuídos de claudina-1 no cólon intestinal. Tais alterações também foram correlacionadas com a disbiose da microbiota intestinal, principalmente com o aumento do filo Verrucomicrobia, principalmente pelo gênero Akkermansia sp. (conhecida por ter espécies degradadora de muco), juntamente com a redução da camada de muco intestinal, permitindo que a microbiota intestinal se aproximasse das células epiteliais intestinais. Sem precedentes, nosso trabalho demonstra uma relação entre o desenvolvimento e a progressão de uma glomerulopatia com inflamação intestinal, disbiose e alterações estruturais do cólon intestinal, associando um efeito protetor renal significativo com depleção da microbiota. Esses resultados fornecem novas informações que sustentam a importância do eixo microbiota-intestino-rim, levantando várias questões e ideias a serem desenvolvidas.
The harm of gut barrier contributes to the pathogenesis of systemic inflammation and progression of many human diseases, including kidney disease. Indeed, the gut-microbiota-kidney axis is gaining power as a possible mechanism to be studied. However, most studies focus on changes in the gut microbiota and its metabolites in chronic kidney diseases, leaving aside early-stage glomerular/podocyte diseases, such as focal segmental glomerulosclerosis (FSGS). In this study, we explored the interrelationship between renal glomerular dysfunction and possible changes in the intestinal microenvironment and gut microbiota. Male Balb/c mice underwent microbiota depletion protocol for 14 days. Then, they were chemically induced to develop FSGS by Doxorubicin (DOX) and were evaluated for another 14 days. In another experiment, without the microbiota depletion, mice were chemically induced to develop the glomerulopathy and were evaluated for 30 days. DOX causes renal histopathological lesions, with decreased number of podocytes per glomerulus, glomerular barrier dysfunction and proteinuria, as well the progression to uremia after 30 days. On the other hand, treated- animals that had previously their gut microbiota depleted exhibited better glomerular barrier function, with lower levels of protein and albumin in the urine, and no structural changes in the kidney. In addition, gut microbiota depletion alters the Th1/Th2 ratio in renal tissue after glomerulopathy, especially by reducing TNF and MCP-1 and by increasing IL-6. Interestingly, after 30 days, glomerular damage was associated with histological changes in gut colon, with increased levels in amorphous cell mass and decreased levels of tight junction protein claudin-1 in gut colon. Such changes were also correlated with gut microbiota dysbiosis, especially with increased Verrucomicrobia phylum, mainly by the genus Akkermansia sp. (known to have mucus-degrading species), along with reduced mucus layer in the intestinal tissue, enabling the gut microbiota to get closer to the intestinal epithelial cells. Unprecedented, our work demonstrates a relationship between the development and progression of a glomerulopathy with gut inflammation, dysbiosis and structural change of the gut colon, associating a significant renal protective effect with microbiota depletion. These results provide new information that supports the importance of the gut-microbiota-kidney axis, raising several questions and ideas to be developed.
The harm of gut barrier contributes to the pathogenesis of systemic inflammation and progression of many human diseases, including kidney disease. Indeed, the gut-microbiota-kidney axis is gaining power as a possible mechanism to be studied. However, most studies focus on changes in the gut microbiota and its metabolites in chronic kidney diseases, leaving aside early-stage glomerular/podocyte diseases, such as focal segmental glomerulosclerosis (FSGS). In this study, we explored the interrelationship between renal glomerular dysfunction and possible changes in the intestinal microenvironment and gut microbiota. Male Balb/c mice underwent microbiota depletion protocol for 14 days. Then, they were chemically induced to develop FSGS by Doxorubicin (DOX) and were evaluated for another 14 days. In another experiment, without the microbiota depletion, mice were chemically induced to develop the glomerulopathy and were evaluated for 30 days. DOX causes renal histopathological lesions, with decreased number of podocytes per glomerulus, glomerular barrier dysfunction and proteinuria, as well the progression to uremia after 30 days. On the other hand, treated- animals that had previously their gut microbiota depleted exhibited better glomerular barrier function, with lower levels of protein and albumin in the urine, and no structural changes in the kidney. In addition, gut microbiota depletion alters the Th1/Th2 ratio in renal tissue after glomerulopathy, especially by reducing TNF and MCP-1 and by increasing IL-6. Interestingly, after 30 days, glomerular damage was associated with histological changes in gut colon, with increased levels in amorphous cell mass and decreased levels of tight junction protein claudin-1 in gut colon. Such changes were also correlated with gut microbiota dysbiosis, especially with increased Verrucomicrobia phylum, mainly by the genus Akkermansia sp. (known to have mucus-degrading species), along with reduced mucus layer in the intestinal tissue, enabling the gut microbiota to get closer to the intestinal epithelial cells. Unprecedented, our work demonstrates a relationship between the development and progression of a glomerulopathy with gut inflammation, dysbiosis and structural change of the gut colon, associating a significant renal protective effect with microbiota depletion. These results provide new information that supports the importance of the gut-microbiota-kidney axis, raising several questions and ideas to be developed.