Three-dimensional microextrusion bioprinting has attracted great interest for fabrication of hierarchically structured, functional tissue substitutes with spatially defined cell distribution. Despite considerable progress, several significant limitations remain such as a lack of suitable bioinks which combine favorable cell response with high shape fidelity. Therefore, in this work a novel bioink of alginate-methylcellulose (AlgMC) blend functionalized with egg white (EW) was developed with the aim of solving this limitation. In this regard, a stepwise strategy was proposed to improve and examine the cell response in low-viscosity alginate inks (3%, w/v) with different EW concentrations, and in high-viscosity inks after gradual methylcellulose addition for enhancing printability. The rheological properties and printability of these cell-responsive bioinks were characterized to obtain an optimized formulation eliciting balanced physicochemical and biological properties for fabrication of volumetric scaffolds. The bioprinted AlgMC + EW constructs exhibited excellent shape fidelity while encapsulated human mesenchymal stem cells showed high post-printing viability as well as adhesion and spreading within the matrix. In a proof-of-concept experiment, the impact of these EW-mediated effects on osteogenesis of bioprinted primary human pre-osteoblasts (hOB) was evaluated. Results confirmed a high viability of hOB (93.7 ± 0.15%) post-fabrication in an EW-supported AlgMC bioink allowing cell adhesion, proliferation and migration. EW even promoted the expression of osteogenic genes, coding for bone sialoprotein (integrin binding sialoprotein/bone sialoprotein precursor (IBSP)) and osteocalcin (BGLAP) on mRNA level. To demonstrate the suitability of the novel ink for future fabrication of multi-zonal bone substitutes, AlgMC + EW was successfully co-printed together with a pasty calcium phosphate bone cement biomaterial ink to achieve a partly mineralized 3D volumetric environment with good cell viability and spreading. Along with the EW-mediated positive effects within bioprinted AlgMC-based scaffolds, this highlighted the promising potential of this novel ink for biofabrication of bone tissue substitutes in clinically relevant dimensions.

These studies were aimed at investigating the potential application of nanoparticles engineered from oil-in-water microemulsion precursors for enhancing immune responses to HIV-1 Tat and Gag p24 proteins. Both of the HIV-1 proteins have been reported to be critical in the virus life cycle and are being evaluated in clinical trials as vaccine candidates. Anionic nanoparticles were prepared using emulsifying wax as the oil phase and Brij 78 and sodium dodecyl sulfate as the surfactants. The resulting nanoparticles were coated with Tat and were demonstrated to produce superior immune responses after administration to BALB/c mice compared to Tat adjuvanted with Alum. Similarly, cationic nanoparticles were prepared using emulsifying wax and Brij 78 and cetyl trimethyl ammonium bromide as the surfactants. The cationic nanoparticles were investigated for delivery of immunostimulatory adjuvants, namely three Toll-like receptor ligands, for obtaining synergistic enhancements in immune responses to a model antigen, Ovalbumin (OVA). In vitro and in vivo studies were carried out to elucidate possible mechanisms by which nanoparticles may result in enhancements in immune responses. In vitro studies were carried out to evaluate the uptake of nanoparticles into dendritic cells and to assess the release of pro-inflammatory cytokines from dendritic cells in the presence of nanoparicles. In vivo studies were carried out using a MHC class I restricted transgenic mouse model to investigate the potential for nanoparticles coated with OVA to enhance presentation of the protein to CD8+ T cells compared to OVA alone. Finally, the preparation of nanoparticles with a low amount of surface chelated nickel for high affinity binding to histidine-tagged (his-tag) proteins was investigated. It was hypothesized that this strengthened interaction of his-tag protein to the nickel chelated nanoparticles (Ni-NPs) would result in a greater uptake of antigen in vivo; therefore, enhanced immune responses compared to protein bound to anionic nanoparticles. In vivo evaluation of his-tag HIV-1 Gag p24 bound to Ni-NPs resulted in enhanced immune responses compared to protein either adjuvanted with Alum or coated on the surface of nanoparticles.

O câncer compreende uma doença multifatorial responsável por altíssimos indíces de mortalidade globalmente. Embora atualmente tenhamos resultados positivos em relação ao tratamento do câncer principalmente voltados à imunoterapia, dados alarmantes ainda são encontrados. Assim, desenvolvemos linhagens tumorais geneticamente modificadas para expressarem ovalbumina (mOVA ou cOVA) e luciferase, a fim de estudarmos as interações do sistema imune com o tumor. Em nossos resultados, a presença da ovalbumina indicou: Alteração no perfil de crescimento tumoral em animais previamente imunizados com OVA e posteriormente desafiados com o tumor, ativação de células TCD8+ citóxicas anti-OVA além de demonstrar também a capacidade imunogênica das linhagens tumorais quando estas são administradas nos animais em estado necrótico. Ao todo, nosso modelo demonstrou que estratégias de vacinação anti-tumorais possuem a capacidade de ativação do sistema imune para na otimização do reconhecimento e resposta anti-tumoral. / Cancer is characterized as a multifactorial disease responsible for many deaths globally. Although nowadays we can find positive perspectives regarding cancers treatment, it is still very common to notice some alarming data. Therefore, our group developed some genetically modified tumoral lineages expressing ovalbumin (mOVA or cOVA) together with luciferase, in order to elucidate the relationship between tumor and the immune system. In our results, the presence of ovalbumin demonstrated: Changes in tumoral growth when animals were previously immunized with OVA and then challenged with our tumoral lineages; TCD8+ lymphocytes anti-OVA activation thus ovalbumin immunogenic potential when lineages were exposed to necrotic death followed by in vivo administration. In summary, our model showed that anti-tumoral vaccinations are indeed capable of promoting immune systems activation and consequently, improving the anti-tumor immunity.

O treinamento físico (TF) melhora a resposta imune de indivíduos saudáveis e traz benefícios para o paciente asmático, mas seu papel na resposta alérgica é desconhecido. Objetivo: Avaliar o papel do TF de moderada intensidade na inflamação pulmonar alérgica crônica. Métodos: 54 cobaias, divididas em 4 grupos: grupo controle (C) (não sensibilizados e não treinados), grupo OVA (sensibilizados à ovalbumina (OVA) e não treinados), grupo treinamento físico (TF) (não sensibilizados e submetidos a um TF), e grupo OVA+TF (sensibilizados à OVA e submetidos a um TF). A sensibilização à OVA teve duração de 8 semanas e o programa de TF de 6 semanas iniciando 15 dias após o início da sensibilização. Cada grupo foi dividido em 2 subgrupos. No primeiro foi avaliada a inflamação pulmonar e os níveis de óxido nítrico exalado (NOex) e no segundo, a hiperresponsividade brônquica à metacolina (Mch). Resultados: A sensibilização à OVA induziu a um aumento da densidade de eosinófilos e linfócitos, expressão de IL(interleucina)-4 e IL-13 e na espessura do músculo liso na via aerea assim como espessura do epitélio comparado aos animais não-sensibilizados (p<0,05). Os animais do grupo OVA+TF apresentaram uma redução da densidade de eosinófilos, linfócitos, IL-4 e IL-13 comparado com o grupo OVA (p<0,05). Nem a sensibilização crônica a OVA ou TF influenciaram a expressão das citocinas Th1 (IL-2 e IFN-) ou a expressão das citocinas regulatórias (IL-10 e IL-1-ra) e nos níveis de NOex. Os grupos que realizaram TF tiveram aumento na espessura do epitélio quando comparados com grupos não-treinados embora não há diferença entre os grupos na avaliação da hiperresponsividade brônquica. Conclusão: Nossos resultados sugerem que o TF reduz a inflamação alérgica sem modificar a hiperresponsividade brônquica e o remodelamento das vias aéreas / Background: Aerobic training (TF) has a positive effects on health subjects and bring benefits on the immune system of asthmatic patients. However, its role on allergic immune response remains poorly understood. Objective: To evaluate the effects of TF in chronic allergic inflammation. Methods: Fiftyfour animals, divided in 4 groups: non-trained and non-sensitized (C), nonsensitized and aerobic exercise (TF), ovalbumin sensitized and non-trained (OVA), and sensitized and aerobic exercise (OVA+TF). OVA or saline sensitization was performed during 8 weeks. TF was performed in a treadmill during 6 weeks beginning in the 3rd week of sensitization. Each group were divided in two groups. In the first one, it was evaluated airway inflammation and levels of exhaleted oxide nitric (NOex), on the second, airway hyperresponsiveness to a methacholine (Mch). Results: OVA sensitization induced an increase in the eosinophils and lymphocytes counting, expression of IL-4 and IL-13 and the amount of airway smooth muscle and epithelium thickness compared to non-sensitized animals (p<0.05). Sensitized animals submitted to TF presented a reduction in the eosinophil and lymphocyte counting, expression of IL-4 and IL-13 compared with OVA group (p<0.05) but not OVA-induced changes in airway remodeling (p>0.05). Neither OVA nor TF induced any difference in the expression of Th1 (IL-2 and IFN-) and regulatory cytokine (IL-10 and IL1-ra) and the levels of NOex. Trained groups presented an increase in epithelium thickness as compared to the nontrained groups however we did not find difference between groups on hyperresponsiveness avaliation. Conclusion: Our results suggest that TF reduces allergic airway inflammation without changes in bronchial hyperresponsiveness and airway remodeling

The eosinophil is a leukocyte whose intracellular mediators are considered to play a central role in the pathogenesis of allergic diseases, including allergic asthma, allergic rhinitis and atopic dermatitis, and which is also involved in immunological responses to parasites. Eosinophil differentiation and maturation from bone marrow progenitors is regulated by interleukin-5 (IL-5), which may be secreted by T helper 2 (Th2) T lymphocytes, and is consistently upregulated in allergic conditions. Eotaxin is a potent chemoattractant for circulating and tissue eosinophils, and the production of this chemokine promotes eosinophil infiltration and accumulation within sites of allergic inflammation.¶ Eosinophils obtained from inflammatory tissues and secretions display an altered phenotype in comparison to peripheral blood eosinophils, with increased surface expression of major histocompatibility complex (MHC) proteins and adhesion molecules (Hansel et al., 1991), and migration across the microvascular endothelium may also increase their capacity to generate an oxidative burst (Walker et al., 1993; Yamamoto et al., 2000). Eosinophils are phagocytic cells, and have been shown to present simple (no requirement for intracellular processing) and complex antigens to MHC-restricted, antigen-specific T lymphocytes (Del Pozo et al., 1992; Weller et al., 1993). Furthermore, eosinophils express the costimulatory molecules required for effective antigen presentation (Tamura et al., 1996), and ligation of costimulatory molecules on the eosinophil cell surface can induce the release of eosinophil derived cytokines (Woerly et al., 1999; Woerly et al., 2002). Therefore the eosinophil may also regulate immune responses.¶ To date, no studies have demonstrated the ability of eosinophils to modulate activated T lymphocyte function via presentation of relevant antigen in the context of MHC class II (MHC-II), concomitant with Th2 cytokine release. In the experiments described in this thesis, murine eosinophils have been observed to rapidly migrate to sites of antigen deposition within the airways mucosa of naïve mice, suggesting a potential role for this granulocyte in the primary response to inhaled antigen. However, human allergic diseases are often diagnosed after the establishment of allergic responses, and symptom development. Therefore, a murine model of allergic airways disease (AAD) was used to investigate the ability for eosinophils to participate as antigen presenting cells (APCs), and thereby modulate activated T lymphocyte function both in vitro and in vivo. Detailed histological analysis of the pulmonary draining lymph nodes following antigen challenge in sensitised mice revealed a rapid infiltration of eosinophils into this tissue, which preceded the accumulation of eosinophils in bronchoalveolar lavage fluid (BALF). This suggested that eosinophils were preferentially translocating to the draining lymph nodes following antigen challenge, and that the subsequent accumulation of these cells in the BALF was a consequence of continued antigen delivery to the lower airways.¶ Eosinophil trafficking to lymphoid tissue via the afferent lymphatics was substantiated using electron microscopy of lymph node sections and the intravenous (i.v.) transfer of fluorescently labeled eosinophils, which did not traffic to lymph nodes via the blood. During the resolution of AAD, eosinophils were noted for their persistence in the pulmonary draining lymph nodes. These observations suggested a continued modulation of T cell function by lymph node dwelling eosinophils during AAD resolution, particularly in light of recent observations for draining lymph node T cell proliferation following instillation of antigen-pulsed eosinophils into the allergic mouse lung (Shi et al., 2000).¶ To further investigate the antigen presenting capacity, eosinophils were obtained from the BALF of mice with AAD, and their surface expression of MHC class II (MHC-II) proteins and costimulatory molecules confirmed using flow cytometric analysis. The ability to acquire and process complex antigen both in vitro and in vivo was also confirmed using naturally quenching fluorescenated ovalbumin (OVA), which is degraded into fluorescent peptides by the action of intracellular proteases. Thus, eosinophil expression of the surface molecules necessary for effective antigen presentation was confirmed, as was their ability to process complex antigen. Further investigations revealed that eosinophils can present complex OVA antigen to CD4+ T lymphocytes obtained from the allergic mouse, and to in vitro derived OVA-specific Th2 cells. In the presence of exogenous antigen, eosinophils co-cultured with T lymphocytes were able to induce Th2 cytokine production, and demonstrated an ability for eosinophils to modulate T lymphocyte function in vitro.¶ The ability for eosinophils to act as antigen presenting cells in vivo was also investigated. Eosinophils obtained from the antigen-saturated lungs of OVA sensitised and challenged mice were transferred to the peritoneal cavities of naïve host mice. When subsequently challenged with aerosolised OVA, eosinophil recipients developed a pulmonary eosinophilia similar to that of OVA sensitised and challenged mice. To validate this finding, the experimental procedure was altered to accommodate the use of non-allergy derived eosinophils, which were pulsed with OVA in vitro, prior to transfer into naïve recipients. When subsequently challenged with aerosolised OVA, eosinophil recipients developed a peripheral blood and pulmonary eosinophilia, and stimulation with OVA induced IL-5 and IL-13 cytokine production from pulmonary draining lymph node cells. Notably, the AAD induced by transfer of antigen pulsed eosinophils did not induce detectable OVA-specific IgG1, which may be attributed to the lack of soluble antigen required for B cell antibody production.¶ During the course of these investigations, an OVA T cell receptor (TCR) transgenic mouse (OT-II) was procured with a view to defining the interaction between eosinophils and activated T lymphocytes (Barnden et al., 1998). Despite having specificity for the OVA323-339 peptide, an immunodominant epitope that skews naïve T cell responses towards Th2 cytokine release (Janssen et al., 2000), T lymphocytes from the OT-II mouse preferentially secreted IFN-γ in response to stimulation with either OVA peptide or OVA. These mice were further characterised in a mouse model of AAD, and found to be refractory to disease induction and progression, which may be attributed to significant IFN-γ secretion by transgenic CD4+ T lymphocytes during antigen sensitisation. Indeed, these cells were noted for their ability to attenuate pulmonary eosinophilia when transferred to OVA sensitised and challenged wild type mice, although serum OVA-specific IgG1, peripheral blood eosinophilia levels and airways response to methacholine challenge remained intact.¶ Knowledge of the biased Th1 phenotype in naïve OT-II provided a unique opportunity to investigate the fate of T lymphocytes bearing high affinity OVA-specific TCRs following neonatal antigen exposure to soluble OVA. In a previous study, subcutaneous (s.c.) administration of soluble OVA to wild type neonatal mice was suspected to have deleted OVA-specific T cells from the T cell repertoire (Hogan et al., 1998a). Using flow cytometry and TCR specific antibody, the delivery of s.c. OVA to OT-II neonates did not alter transgenic T cell populations in adult mice. Instead, it was surprising to find a skewing towards the Th2 phenotype and loss of IFN-γ secretion following OVA sensitisation and challenge in adult mice. A mechanism for this reprogramming of the transgenic T cell from the Th1 to a Th2 phenotype following OT-II neonatal exposure to soluble OVA is proposed, and further experimentation may validate this hypothesis.¶ In conclusion, eosinophils residing in the allergic lung have the capacity to interact with activated T cells, both within this tissue and the draining lymph nodes. Despite their relative inefficiency as antigen presenting cells (Mawhorter et al., 1994), eosinophils may participate en masse in the serial triggering of activated TCRs, and provide appropriate costimulatory signals that modulate T lymphocyte function. Through the elaboration of Th2 cytokines and stimulation of T cell proliferation, antigen presenting eosinophils may transiently prolong or exacerbate the symptoms of allergic diseases. Alternatively, eosinophils presenting relevant antigens may inhibit T cell activity via degranulation, and such activity has recently been observed in a parasite model (Shinkai et al., 2002). Finally, experiments in the OT-II mouse have provided valuable information to suggest that therapies designed to modulate eosinophil numbers in allergic tissues through the secretion of opposing cytokines such as IFN-γ, may be of limited benefit. The results shown here suggest that airways dysfunction remains intact despite significantly reduced pulmonary eosinophilia

Made available in DSpace on 2015-05-14T13:00:11Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2644910 bytes, checksum: 94bc3ca3dd5252435423f525d32a2ea9 (MD5) Previous issue date: 2009-04-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Asthma is a chronic inflammatory disease characterized by cell migration and bronchial hyperreactivity (HRB). One strategy to treat allergic diseases is the development of new drugs with good efficacy and few side effects. Flavonoids are plant compounds known for its antioxidant, antiallergic and anti-inflammatory activities. Based on this premise, the study aimed to select flavonoids by the immunopharmacological screening and to evaluate prophylactic and therapeutic treatments in the experimental asthma model. For this purpose the flavonoids tested were myricetin, isoramnetin and glycosylated kampherol known as 3-O-[β-D-glycopiranosil-(1→6)-α-L-rhamnopyranosyl]-7-O-α-L-rhamnopyranosyl-kamferol (GRRK). The experimental model was BALB/c mice sensitized and challenged with ovalbumin (OVA) and the treatments were before (prophylactic) or after (therapeutic) to establishment of the experimental asthma model. The three flavonoids inhibited the animal death during the anaphylactic chock reaction induced by OVA and the inflammatory cell migration to the lung; however only the GRRK was used in the following experiments because of its best yield in the purification process. Both prophylactic and therapeutic treatments with GRRK (30 mg/kg) decreased significantly the total number of inflammatory cells (P< 0.05), eosinophils cells (P< 0.05), IL-5 (P< 0.05) and IL-13 (P< 0.05) production from bronchoalveolar lavage (BAL), IgE OVA-specific title (P< 0.01) in the sera, the bronchial hyperreactivity (HRB) (P< 0.05) induced by methacholine and mucus production (P< 0.001) by the globbet cells from the lung as compared with non-treated GRRK animals. The results obtained in the different treatments with GRRK were statistically comparable with that observed in the OVA-sensitized group treated with dexametasone. Moreover, treatment with GRRK was able to reduce the number of CD4+ T cells (p <0.001), B cells (p <0.001), expression of major complex of compatibility II class (MHC II class) and CD40 molecules in the antigen presenting cells (CD11b+ CD11c+) from BAL. Although the GRRK induced a suppressive effect in the Th2 immune response it was not able to exacerbate the Th1 immune response by IFN- production. The production of this cytokine was not modified when compared with non treated animals. The GRRK treatment also was not able to modify the regulatory immune response because there was no significant change in the production of TGF- and the number of TCD4+Foxp3+, a marker of LT regulatory (TReg). These results demonstrated that GRRK treatment before (prophylactic) or after (therapeutic) the establishment of allergic asthma, restored the morpho-functional changes in the airways by Th2-dependent immunossupression, although independent of Th1 and TReg. / A asma é uma doença inflamatória crônica caracterizada por migração celular para os pulmões e hiperreatividade brônquica (HRB). Uma estratégia para o tratamento de doenças alérgicas é o desenvolvimento de novos medicamentos com boa eficácia e poucos efeitos colaterais. Flavonóides são compostos derivados de plantas conhecidos por suas atividades antioxidante, antialérgica e antiinflamatória. Partindo desta premissa, o trabalho teve como objetivo selecionar flavonóides a partir de análises imunofarmacológicas e avaliar os tratamentos profiláticos ou terapêuticos no modelo de asma alérgica experimental. Para tal, os flavonóides testados foram: myricetina, isoramnetina e kanferol glicosilado conhecido por 3-O-[β-D-glycopiranosil-(1→6)-α-L-ramnopiranosil]-7-O-α-L-ramnopiranosil-kanferol (GRRK). O modelo experimental foi realizado em camundongos BALB/c sensibilizados e desafiados com ovalbumina (OVA) e os tratamentos foram antes (profilático) ou após (terapêutico) estabelecer o modelo de asma alérgica experimental. Os três flavonóides inibiram a morte dos animais durante o choque anafilático induzido por OVA e a migração de células da inflamação para os pulmões, entretanto, apenas o GRRK foi usado nos demais experimentos, devido ao seu melhor rendimento no processo de purificação. Os tratamentos profilático e terapêutico com GRRK (30 mg/kg) diminuíram, de forma significativa, o número total de células inflamatórias (P< 0,05), de eosinófilos (P< 0,05) a produção de IL-5 (P< 0,05) e IL-13 (P< 0,05) no lavado broncoalveolar (LBA), o título de IgE-OVA-específica (P< 0,01) no soro, a hiperreatividade brônquica (HRB) (P< 0,05) induzida com metacolina e a produção de muco (P< 0,001) pelas células caliciformes de pulmão quando comparados com os animais não tratados com GRRK e sensibilizado com OVA. Os resultados obtidos nos diferentes tratamentos com GRRK foram comparáveis estatisticamente aos efeitos observados no grupo de animais tratados com a droga padrão dexametasona. Além disso, o tratamento com GRRK foi capaz de diminuir: o número de linfócitos T CD4+ (P< 0,001) e de linfócitos B (P< 0,001), a expressão de moléculas de classe II do complexo principal de histocompatibilidade (MHC II) e da molécula CD40 em células apresentadoras de antígeno (CD11b+CD11c+) do LBA. Embora o tratamento com GRRK tenha induzido um efeito supressor na resposta imune de perfil Th2, não foi capaz de exacerbar a resposta imune Th1 com a produção de IFN- A produção desta citocina se manteve inalterada quando comparada ao grupo de animais não tratados. O tratamento também não foi capaz de alterar a reposta imune reguladora, pois não houve mudança significativa na produção de TGF- e no número de células TCD4+Foxp3+, marcador de LT regulador (LTReg). Esses resultados demonstram que o tratamento com GRRK antes (profilático) ou depois (terapêutico) de estabelecer a asma alérgica experimental, restabeleceu as alterações morfofuncionais das vias aéreas, por um mecanismo modulador das células Th2, embora independente de Th1 e de Treg

O câncer compreende uma doença multifatorial responsável por altíssimos indíces de mortalidade globalmente. Embora atualmente tenhamos resultados positivos em relação ao tratamento do câncer principalmente voltados à imunoterapia, dados alarmantes ainda são encontrados. Assim, desenvolvemos linhagens tumorais geneticamente modificadas para expressarem ovalbumina (mOVA ou cOVA) e luciferase, a fim de estudarmos as interações do sistema imune com o tumor. Em nossos resultados, a presença da ovalbumina indicou: Alteração no perfil de crescimento tumoral em animais previamente imunizados com OVA e posteriormente desafiados com o tumor, ativação de células TCD8+ citóxicas anti-OVA além de demonstrar também a capacidade imunogênica das linhagens tumorais quando estas são administradas nos animais em estado necrótico. Ao todo, nosso modelo demonstrou que estratégias de vacinação anti-tumorais possuem a capacidade de ativação do sistema imune para na otimização do reconhecimento e resposta anti-tumoral. / Cancer is characterized as a multifactorial disease responsible for many deaths globally. Although nowadays we can find positive perspectives regarding cancers treatment, it is still very common to notice some alarming data. Therefore, our group developed some genetically modified tumoral lineages expressing ovalbumin (mOVA or cOVA) together with luciferase, in order to elucidate the relationship between tumor and the immune system. In our results, the presence of ovalbumin demonstrated: Changes in tumoral growth when animals were previously immunized with OVA and then challenged with our tumoral lineages; TCD8+ lymphocytes anti-OVA activation thus ovalbumin immunogenic potential when lineages were exposed to necrotic death followed by in vivo administration. In summary, our model showed that anti-tumoral vaccinations are indeed capable of promoting immune systems activation and consequently, improving the anti-tumor immunity.

O treinamento físico (TF) melhora a resposta imune de indivíduos saudáveis e traz benefícios para o paciente asmático, mas seu papel na resposta alérgica é desconhecido. Objetivo: Avaliar o papel do TF de moderada intensidade na inflamação pulmonar alérgica crônica. Métodos: 54 cobaias, divididas em 4 grupos: grupo controle (C) (não sensibilizados e não treinados), grupo OVA (sensibilizados à ovalbumina (OVA) e não treinados), grupo treinamento físico (TF) (não sensibilizados e submetidos a um TF), e grupo OVA+TF (sensibilizados à OVA e submetidos a um TF). A sensibilização à OVA teve duração de 8 semanas e o programa de TF de 6 semanas iniciando 15 dias após o início da sensibilização. Cada grupo foi dividido em 2 subgrupos. No primeiro foi avaliada a inflamação pulmonar e os níveis de óxido nítrico exalado (NOex) e no segundo, a hiperresponsividade brônquica à metacolina (Mch). Resultados: A sensibilização à OVA induziu a um aumento da densidade de eosinófilos e linfócitos, expressão de IL(interleucina)-4 e IL-13 e na espessura do músculo liso na via aerea assim como espessura do epitélio comparado aos animais não-sensibilizados (p<0,05). Os animais do grupo OVA+TF apresentaram uma redução da densidade de eosinófilos, linfócitos, IL-4 e IL-13 comparado com o grupo OVA (p<0,05). Nem a sensibilização crônica a OVA ou TF influenciaram a expressão das citocinas Th1 (IL-2 e IFN-) ou a expressão das citocinas regulatórias (IL-10 e IL-1-ra) e nos níveis de NOex. Os grupos que realizaram TF tiveram aumento na espessura do epitélio quando comparados com grupos não-treinados embora não há diferença entre os grupos na avaliação da hiperresponsividade brônquica. Conclusão: Nossos resultados sugerem que o TF reduz a inflamação alérgica sem modificar a hiperresponsividade brônquica e o remodelamento das vias aéreas / Background: Aerobic training (TF) has a positive effects on health subjects and bring benefits on the immune system of asthmatic patients. However, its role on allergic immune response remains poorly understood. Objective: To evaluate the effects of TF in chronic allergic inflammation. Methods: Fiftyfour animals, divided in 4 groups: non-trained and non-sensitized (C), nonsensitized and aerobic exercise (TF), ovalbumin sensitized and non-trained (OVA), and sensitized and aerobic exercise (OVA+TF). OVA or saline sensitization was performed during 8 weeks. TF was performed in a treadmill during 6 weeks beginning in the 3rd week of sensitization. Each group were divided in two groups. In the first one, it was evaluated airway inflammation and levels of exhaleted oxide nitric (NOex), on the second, airway hyperresponsiveness to a methacholine (Mch). Results: OVA sensitization induced an increase in the eosinophils and lymphocytes counting, expression of IL-4 and IL-13 and the amount of airway smooth muscle and epithelium thickness compared to non-sensitized animals (p<0.05). Sensitized animals submitted to TF presented a reduction in the eosinophil and lymphocyte counting, expression of IL-4 and IL-13 compared with OVA group (p<0.05) but not OVA-induced changes in airway remodeling (p>0.05). Neither OVA nor TF induced any difference in the expression of Th1 (IL-2 and IFN-) and regulatory cytokine (IL-10 and IL1-ra) and the levels of NOex. Trained groups presented an increase in epithelium thickness as compared to the nontrained groups however we did not find difference between groups on hyperresponsiveness avaliation. Conclusion: Our results suggest that TF reduces allergic airway inflammation without changes in bronchial hyperresponsiveness and airway remodeling

INTRODUÇÃO: A importância do parênquima pulmonar na piora funcional da asma tem sido recentemente investigada. Embora a ativação da enzima óxido nítrico sintase induzida (iNOS) amplifique a responsividade e o remodelamento das vias aéreas induzidos pela inflamação crônica, seu efeito no parênquima pulmonar não foi previamente estudado. OBJETIVO: Avaliar a influência do óxido nítrico derivado da iNOS na mecânica pulmonar, na inflamação e no processo de remodelamento no tecido pulmonar periférico de cobaias com inflamação pulmonar alérgica. MÉTODOS: Os animais foram submetidos a sete inalações com doses crescentes de ovalbumina (1~5 mg/mL) ou soro fisiológico por 4 semanas. As cobaias receberam 1400-W (inibidor específico de iNOS, intraperitoneal) ou veículo por 4 dias, iniciando 30 minutos antes da sétima inalação. Após 72h da sétima inalação, os animais foram anestesiados, exsanguinados e fatias de tecido pulmonar periférico foram retiradas e suspensas em banho orgânico de Krebs, e a resistência e elastância tecidual foram avaliadas em condição basal e após desafio com ovalbumina. Após, as fatias de tecido pulmonar periférico foram submetidas à avaliação histopatológica. RESULTADOS: Os animais expostos às inalações com ovalbumina apresentaram valores maiores de porcentagem de aumento da resistência e da elastância tecidual em relação ao basal após desafio com ovoalbumina no banho (p<0.05). Houve aumento no número de eosinófilos (p<0.001), nas células iNOS positivas (p<0.001), na deposição de fibras elásticas e colágenas (p<0.05), na densidade de actina (p<0.05) e na expressão de 8-epi-PGF2a (p<0.001) no septo alveolar. A administração de 1400-W reduziu todos estes parâmetros funcionais e morfológicos (p<0.05). CONCLUSÕES: Neste modelo experimental, o bloqueio específico da iNOS atenuou a constrição, a inflamação e o remodelamento no parênquima pulmonar. Estas alterações podem estar relacionadas aos efeitos do óxido nítrico na modulação da via do estresse oxidativo. O presente estudo sugere que a inibição específica da iNOS pode amplificar as estratégias terapêuticas utilizadas na abordagem de doenças inflamatórias crônicas pulmonares. / INTRODUCTION: The importance of lung parenchyma in functional asthma impairment has been recently addressed. Although the inducible nitric oxide synthase (iNOS) activation amplifies chronic inflammation-induced airway responsiveness and remodeling, its effect on lung parenchyma has not been previously investigated. OBJECTIVE: To evaluate the influence of iNOSderived NO in the pulmonary mechanics, inflammation, and remodeling processes in peripheral lung tissue of guinea pigs with pulmonary allergic inflammation. METHODS: Animals were submitted to seven ovalbumin exposures with increasing doses (1~5 mg/mL) or saline for 4 weeks. The guinea pigs received 1400-W (iNOS-specific inhibitor, intraperitoneal) or vehicle for 4 days, beginning 30 minutes before the 7th inhalation. At 72h after the 7th inhalation, animals were anesthetized, exsanguinated and peripheral lung tissue strips were retreat and suspended in a Krebs organ bath, and the tissue resistance and elastance were evaluated at baseline condition and after ovalbumin challenge. After that, strips were submitted to histopathological evaluation. RESULTS: The ovalbumin-exposed animals presented greater values of percentage of increase of tissue resistance and elastance related to baseline after ovalbumin challenge in the bath (p<0.05). There were increase in the number of eosinophils (p<0.001) and iNOSpositive cells (p<0.001), in collagen and elastic fiber deposition (p<0.05), in actin density (p<0.05) and in 8-epi-PGF2a expression (p<0.001) in the alveolar septa. The 1400-W administration reduced all these functional and morphological parameters (p<0.05). CONCLUSIONS: In this experimental model, the iNOS-specific blockage attenuated constriction, inflammation, and remodeling in the lung parenchyma. These alterations may be related to NO effects in the modulation of the oxidative stress pathway. The present study suggests that specific iNOS inhibition can amplify the therapeutics strategies used in the management in chronic inflammatory lung diseases.

A tolerância pode ser considerada um dos pilares da imunologia. Sabe-se que a tolerância a um antígeno pode gerar tolerância a outro antígeno não relacionado, fenômeno conhecido como tolerância cruzada. Neste trabalho caracterizamos a tolerância cruzada utilizando a OVA como tolerógeno e extrato de Blomia tropicalis (Bt) ou Hemocianina de Keyhole limpet (KLH) como alérgenos. Verificamos que é possível reproduzir o fenômeno da tolerância cruzada neste modelo de inflamação alérgica induzida tanto pelo KLH quanto pela Bt, com diminuição do infiltrado inflamatório no pulmão, eosinófilos, IgE total e produção de muco. Ainda, a estratégia de utilizar a tolerância cruzada terapeuticamente, i.é., após a sensibilização com KLH, a indução de tolerância cruzada não foi capaz de prevenir a resposta alérgica. Em conjunto, nossos dados mostram que a tolerância à OVA modifica as respostas alérgicas tanto à Bt quanto ao KLH no modelo de inflamação pulmonar experimental de forma profilática, mas que a tolerância cruzada não é eficiente em animais já sensibilizados. / Tolerance is among the Immunology pillars. Experimental data indicate that tolerance towards an antigen can promote tolerance to an unrelated antigen, a phenomenon known as cross-tolerance. Here we sought to characterize cross tolerance using OVA as a tolerogen and Blomia tropicalis (Bt) extract or Keyhole limpet Hemocianina (KLH) as allergens. We found that cross tolerance can be reproduced in the model of allergic lung disease induced by KLH or Bt, with less inflammatory infiltrate in the lung, eosinophils, total IgE and mucus production. Using cross tolerance therapeutically, i.e., after KLH sensitization, was not effective, since the allergic lung response was not modulated. Altogether, our data shows that OVA tolerance modulate allergic lung disease induced either by Bt or KLH when used as prophylactic model, however cross tolerance is ineffective in sensitized animals.