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Previous issue date: 2017-03-03 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Background: asthma is a heterogeneous disease characterized by chronic inflammation of the lower airways. The inflammatory process is associated with bronchial hyperresponsiveness, resulting in recurrent episodes of wheezing, coughing, dyspnea and chest tightness. Asthma affects around 300 million people worldwide, with high prevalence, mainly in children. Chronic inflammation in the airways of patients with asthma is complex and involves a range of cells from the immune system, including T lymphocytes, granulocytes, epithelial cells, among others. Granulocytes are considered key cells to maintain inflammation. Neutrophils and eosinophils have different characteristics and functions for the immune response in asthma. Both type of cells release a variety of mediators that contribute to chronic inflammation and changes in the structure of the airways, secondary to external agents. In this context, it was demonstrated that after activation neutrophils and eosinophils are able to release extracellular DNA "traps" with specific proteins that kill extracellular pathogens. On the other hand, it is possible that these DNA "traps" contribute to immunopathology in chronic inflammatory diseases, such as asthma. Therefore, it has recently been shown that neutrophils and eosinophils generate extracellular DNA traps in the airways of asthmatics, possibly contributing to tissue damage.
Objective: to verify whether there is extracellular DNA traps and the presence of inflammatory cells in sputum samples of children and adolescents with asthma.
Methods: this cross-sectional study selected children and adolescents with asthma, between 6 and 18 years of age, in a regular follow-up at a reference center from southern Brazil. We have performed lung function (spirometry), allergen skin test, and induced sputum to identify the inflammatory cells profile, formation of extracellular DNA traps, and quantification of extracellular DNA. To visualize the extracellular DNA traps, the cells were stained with Hoechst 33342. The images were captured on a fluorescence confocal microscope.
Results: 18 children and adolescents were included, 13 with severe asthma and 5 with non-severe asthma. Of these, 17 (94.4%) had a positive skin test for some type of allergens and all patients presented pulmonary function within the limits of normality. Patients with inflammatory cell profiles in sputum (7,12 [4,41,45,23]) showed a significant increase (p = 0.01) in extracellular DNA concentrations compared to patients with pauci-granulocytic profile (2.31 [1.47-3.56]). The extracellular DNA levels correlated positively (r = 0.73, p = 0.004) with the total granulocytic cells in the sputum of these patients. Likewise, there was a significant positive correlation between extracellular DNA and absolute sputum neutrophil counts (r = 0.71, p = 0.008) and absolute sputum eosinophils counts (r = 0.69; p = 0.0013) in the sputum samples.
Conclusion: Our results show the presence of extracellular DNA traps in sputum with inflammatory pattern of children and adolescents with asthma suggesting that these traps are released by granulocytic cells, specifically neutrophils and eosinophils. / Base te?rica: a asma ? uma doen?a heterog?nea, caracterizada pela inflama??o cr?nica das vias a?reas inferiores. O processo inflamat?rio est? associado ? hiper-responsividade br?nquica, tendo como consequ?ncia, epis?dios recorrentes de sibil?ncia, tosse, dispneia e opress?o tor?cica. A doen?a atinge em torno de 300 milh?es de pessoas no mundo, sendo considerada uma doen?a com elevada preval?ncia, principalmente na popula??o infantil. A inflama??o cr?nica presente nas vias a?reas de indiv?duos com asma ? complexa e envolve um conjunto de c?lulas provenientes do sistema imunol?gico, incluindo linf?citos T, granul?citos, c?lulas epiteliais, entre outras. Os granul?citos s?o considerados c?lulas fundamentais para sustentar a inflama??o. Os neutr?filos e os eosin?filos apresentam caracter?sticas e fun??es diferentes para a resposta imune na asma. Ambos liberam uma variedade de mediadores que contribuem para inflama??o cr?nica e altera??es na estrutura das vias a?reas, com est?mulos externos. Neste contexto, foi demonstrado que os neutr?filos e eosin?filos, ap?s ativa??o, s?o capazes de liberar ?armadilhas? de DNA extracelular com prote?nas espec?ficas, que combatem agentes patog?nicos extracelularmente. Por outro lado, ? poss?vel que essas ?armadilhas? de DNA contribuam para a imunopatologia em doen?as inflamat?rias cr?nicas, como na asma. Portanto, recentemente, foi identificado que neutr?filos e eosin?filos geram redes extracelulares de DNA nas vias a?reas de asm?ticos adultos.
Objetivo: verificar se existe forma??o de redes extracelulares de DNA com a presen?a de c?lulas inflamat?rias em amostra de escarro de crian?as e adolescentes com asma.
M?todos: nosso estudo transversal selecionou crian?as e adolescentes com asma, entre 6 e 18 anos de idade, em acompanhamento regular em um centro de refer?ncia do sul do Brasil. Foram coletados dados relativos a fun??o pulmonar (espirometria), teste cut?neo para al?rgenos, e escarro induzido para identifica??o do perfil de c?lulas inflamat?rias, forma??o das redes extracelulares de DNA, e quantifica??o do DNA extracelular. Para a visualiza??o das redes extracelulares de DNA, as c?lulas foram coradas com Hoechst 33342. As imagens foram capturadas em microsc?pio confocal de fluoresc?ncia. Resultados: foram inclu?dos 18 crian?as e adolescentes, sendo 13 com asma grave e 5 n?o grave. Destes, 17 (94,4%) obtiveram o teste cut?neo positivo para algum tipo de al?rgenos e todos apresentaram fun??o pulmonar dentro dos limites da normalidade. Os pacientes com perfil de c?lulas inflamat?rias (7,12 [4,41-45,23]) obtiveram um aumento significativo (p=0,01) nas concentra??es extracelulares de DNA quando comparados com pacientes com perfil pauci-granuloc?tico (2,31[1,47-3,56]). Os n?veis de DNA extracelular correlacionaram-se positivamente (r=0,73; p=0, 0004) com as c?lulas granuloc?ticas totais no escarro destes pacientes. Do mesmo modo, houve uma correla??o positiva entre o DNA extracelular com a contagem absoluta de neutr?filos (r=0,71; p=0,008) e contagem absoluta de eosin?filos (r=0,69; p=0,0013) nas amostras de escarro.
Conclus?o: nossos resultados mostram a presen?a de redes extracelulares de DNA no escarro com padr?o inflamat?rio em crian?as e adolescentes com asma sugerindo que estas redes s?o liberadas por c?lulas granuloc?ticas, especificamente neutr?filos e eosin?filos.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7499 |
| Date | 03 March 2017 |
| Creators | Silveira, Keila Abreu da |
| Contributors | Pitrez, Paulo M?rcio Condessa |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Medicina/Pediatria e Sa?de da Crian?a, PUCRS, Brasil, Escola de Medicina |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 557290555552975733, 600, 600, 600, 600, -224747486637135387, -969369452308786627, 1802873727776104890 |
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