Avaliação do Recrutamento Celular no Modelo Experimental da Esquistossomose Mansônica

Sendo a Esquistossomose uma doença de grande importância médica, o conhecimento específico da reação inflamatória, assim como o entendimento da resposta imune induzida pelo S. mansoni, nos motivou neste estudo. Alguns pesquisadores demonstraram que, em modelos de cobaias ocorre reações inflamatórias induzidas por este helminto no fígado, assim como no homem. Desta forma, avaliamos a migração de leucócitos para diferentes compartimentos, e identificamos alterações histopatológicas promovidas pela parasita. Nossos achados, demonstraram aumento absoluto e percentual de eosinófilos na cavidade peritoneal e sangue de camundongos infestados pelo S. mansoni. As figuras histológicas confirmaram os achados da cavidade peritoneal onde houve um aumento significativo de eosinófilos, sugerindo que estas células migraram para a cavidade peritoneal posteriormente ao seu aumento no sangue caracterizando a resposta inflamatória intensa na infestação pelo S. mansoni neste modelo experimental

Adipose Tissue-Derived Mesenchymal Stem Cells Increase Skin Allograft Survival and Inhibit Th-17 Immune Response

Adipose tissue-derived mesenchymal stem cells (ADSC) exhibit immunosuppressive capabilities both in vitro and in vivo. Their use for therapy in the transplant field is attractive as they could render the use of immunosuppressive drugs unnecessary. The aim of this study was to investigate the effect of ADSC therapy on prolonging skin allograft survival. Animals that were treated with a single injection of donor allogeneic ADSC one day after transplantation showed an increase in donor skin graft survival by approximately one week. This improvement was associated with preserved histological morphology, an expansion of CD4+ regulatory T cells (Treg) in draining lymph nodes, as well as heightened IL-10 expression and down-regulated IL-17 expression. In vitro, ADSC inhibit naïve CD4+ T cell proliferation and constrain Th-1 and Th-17 polarization. In summary, infusion of ADSC one day post-transplantation dramatically increases skin allograft survival by inhibiting the Th-17 pathogenic immune response and enhancing the protective Treg immune response. Finally, these data suggest that ADSC therapy will open new opportunities for promoting drug-free allograft survival in clinical transplantation

Modulation of Immune alloresponse by Adiposetissue Derived Mesenchymal Stem Cells

A identificação e caracterização das células reguladoras (Treg) trouxeram uma nova perspectiva para a indução da tolerância imunológica nos transplantes e um aumento na sobrevida dos enxertos. Uma vez que as células-tronco mesenquimais derivadas de tecido adiposo (ADSC) possuem a capacidade de suprimir uma resposta imune, nos questionamos se as ADSC poderiam melhorar a sobrevida de um enxerto em camundongos C57BL/6, associada à indução de Treg. Nossos resultados mostram que o tratamento com as ADSC aumentou a média de sobrevida do enxerto, com uma melhora na morfologia do tecido transplantado, um aumento na população de linfócitos Treg e na expressão de IFN-g e IL-10, alem de uma inibição da expressão de IL-17 e na proliferação de células T CD4+. Nossos achados sugerem que as ADSC suprimem a resposta imune ao enxerto por meio da indução de Treg, a qual inibe a participação das células Th17, com uma melhora no enxerto. Estes dados ajudam a desenvolver novos aspectos na estratégia terapêutica e possivelmente o uso futuro dessas células na prática clínica.The identification and characterization de regulatory T cells that can control immune responsiveness to alloantigens opened up opportunities for new therapies in transplantation. After exposure to alloantigens in vivo, antigen-specific immunoregulatory activity is enriched in a population of CD4+ T cells that express high levels of CD25 and Foxp3. Adipose tissue contains one type of mesenchymal stem cells (ADSC) with capacity of suppressing immune response. In this work we propose the correlation of the ADSC cells in ameliorating skin graft survival, and if is associated with Foxp3 expression. Graft survival was enhanced in animals that received ASCs from the donor. Interesting, in the animals treated with ASCs from CBA presented a higher expression of Foxp3+ cells in the lymph-nodes. In treated mice Foxp3 expression was increased and IL-17 were increased in allogeneic group, suggesting a potent inflammatory response inside the graft. So far, these data suggest the ADSCs increase TReg population cells, inhibit IL-17 expression and prolonging skin graft survival

Avaliação do Recrutamento Celular no Modelo Experimental da Esquistossomose Mansônica

Sendo a Esquistossomose uma doença de grande importância médica, o conhecimento específico da reação inflamatória, assim como o entendimento da resposta imune induzida pelo S. mansoni, nos motivou neste estudo. Alguns pesquisadores demonstraram que, em modelos de cobaias ocorre reações inflamatórias induzidas por este helminto no fígado, assim como no homem. Desta forma, avaliamos a migração de leucócitos para diferentes compartimentos, e identificamos alterações histopatológicas promovidas pela parasita. Nossos achados, demonstraram aumento absoluto e percentual de eosinófilos na cavidade peritoneal e sangue de camundongos infestados pelo S. mansoni. As figuras histológicas confirmaram os achados da cavidade peritoneal onde houve um aumento significativo de eosinófilos, sugerindo que estas células migraram para a cavidade peritoneal posteriormente ao seu aumento no sangue caracterizando a resposta inflamatória intensa na infestação pelo S. mansoni neste modelo experimental

ADSC are effective suppressors of CD4⁺ T cell proliferation in an <i>in vitro</i> MLR co-culture and inhibit Th-1/Th-17 polarization.

<p>(A) In an MLR culture, naïve CD4⁺ T cells from the spleens of C57BL/6 mice were stimulated with mature dendritic cells from CBA/J mice for 4 days in the presence or absence of different concentration of ADSC. CD4⁺ T cell proliferation in these cultures was analyzed by flow cytometry. Gates represent the CFSE dilution peaks using FlowJo. (B) Expansion of cell generations was determined using FlowJo. (C) Cell proliferation relative index was determined using FlowJo. (D) Cytokine levels for IL4, IL-10 and IFN-γ from the culture supernatants were analyzed by Bioplex. (E) Intracellular staining for IL-17 and IFN-γ was performed on cultured T cells and analyzed by flow cytometry in gated CD4⁺ T cells using FlowJo.</p

ADSC change the cytokine milieu <i>in vivo</i> and block Th-17 responses.

<p>C57BL/6 mice were grafted with full thickness allogeneic tail skin from CBA/J mice and treated or not with donor (CBA/J) ADSC. Tissues were analyzed on days 3 and 10 after transplantation. RNA was isolated from (A) draining axillary lymph nodes and (B) skin. Gene expression of Foxp3, TGF-β, IL-10, IFN-γ, IL-17 and IL-6 was assessed by quantitative RT-PCR. Samples were normalized by expression of an endogenous housekeeping gene (HPRT). Data are represented as mean ± SEM; <i>n</i> = 3 independent experiments done in triplicate, leading to a total of ≥10 independent values for each point. <i>*P</i><0,05.</p

ADSC confer increased graft survival upon adoptive transfer.

<p>Allogeneic donor CBA/J skin allografts were transplanted onto C57BL/6 recipients. On day +1 following surgery, recipients were separated into three experimental groups: (A) (Allo-ADSC) were injected intraperitoneally with 5×10⁵ ADSC (n = 8); (BMMC) were injected intraperitoneally with 5×10⁵ bone marrow mononuclear cells (n = 6); (B6-ADSC) were injected intraperitoneally with 5×10⁵ ADSC from syngeneic C57BL/6 donors; (Balb/c-ADSC) were injected intraperitoneally with 5×10⁵ ADSC from a third party strain; (Allo) were intraperitoneally with PBS (n = 10). Isogenic skin transplants were used as controls (n = 5). Morphometric analyses from skin histology at day 3 and 10 show: (B) collagen orientation (Sirius red), (C) neutrophil infiltration and (D) necrosis. (E) VEGF quantification was performed by RT-PCR. (F) Numbers represent the percentage of Foxp3⁺ cells within gated CD4⁺ T cells on day 3 from axillary draining lymph nodes. (G) RT-PCR data showing Foxp3, IFN-γ and IL-2 expression in axillary draining lymph nodes and skin on the day of rejection. Data are represented as mean ± SEM; <i>n</i> = 3 independent experiments. <i>*P</i><0.05.</p