A rapid, two-step procedure is described for the isolation of both "high molecular weight" (H-) and "low molecular weight" (L-) plasma kininogens from a single sample of plasma. Affinity chromatography on carboxymethyl-papain-Sepharose is used, together with high-resolution anion exchange chromatography.

Alpha1-proteinase inhibitor (alpha1-PI) has been shown to be a useful marker of gastrointestinal protein loss in some species. The objectives of this study were, first, to develop and analytically validate an ELISA for the measurement of alpha1-PI in feces and serum from cats, and, second, to evaluate fecal alpha1-PI concentrations in healthy cats and cats with chronic gastrointestinal disease. The lower detection limits of the ELISA were 0.02 g/L for serum and 0.04 microgram/gram for feces. The observed-to-expected (O/E) ratios for serial dilutions of serum and fecal samples ranged from 100.0 to 129.7% (mean +/- SD: 112.2 +/- 9.9%) and 103.5 to 141.6% (115.6 +/- 12.8%), respectively. The O/E ratios for samples spiked with seven known concentrations of alpha1-PI ranged from 82.3 to 107.8% (94.7 +/- 7.6%) for serum and 78.5 to 148.7% (96.8 +/- 18.2%) for feces. The coefficients of variation for intra-assay and inter-assay variability were <7.9% and &lt;12.1% for serum, and 5.3%, 11.8%, and 14.2% and 7.7%, 10.2%, and 20.4% for feces, respectively. Reference intervals were 0.6 to 1.4 g/L for serum and up to 1.6 microgram/g for feces. We conclude that this ELISA is sufficiently linear, accurate, precise, and reproducible. For the clinical evaluation, twenty cats with clinical signs of chronic gastrointestinal disease and 20 healthy control cats were enrolled. The diseased cats were grouped into two groups: mild to moderate idiopathic inflammatory bowel disease (IBD) (Group A; n=8) and severe IBD or neoplastic disease (Group B; n=12), based on histopathology results of endoscopic biopsies. Fecal alpha1-PI concentrations and serum concentrations of total protein, albumin, globulin, cobalamin, folate, pancreatic lipase immunoreactivity, and trypsin-like immunoreactivity were determined. Nineteen of the 20 diseased cats had increased fecal alpha1-PI concentrations, ranging from 1.9 to 233.6 microgram/g (normal range: <= 1.6 microgram/g). Fecal alpha1-PI concentrations were statistically significantly different between healthy cats and cats of Group A (median: 3.9 microgram/g, range: 1.3 to 9.2 microgram/g, P<0.001) or cats of Group B (median: 20.6 microgram/g, 4.3 to 233.6 microgram/g; P<0.001), and also between cats of Groups A and B (P<0.01). Hypoalbuminemia, hypoproteinemia, and hypocobalaminemia were detected in 88%, 83%, and 56% of the diseased cats, respectively. Our study suggests that increased fecal alpha1-PI concentrations in association with hypoalbuminemia may be a common finding in cats with IBD or GI neoplasia. Furthermore, alpha1-PI concentrations appear to be higher in cats with severe IBD or confirmed GI neoplasia when compared to cats with mild to moderate IBD.

Master of Science / Department of Entomology / Marcelo Ramalho-Ortigao / Sand flies (Diptera:Psychodidae) are vectors of parasites of the genus Leishmania transmitted to suitable vertebrate host during blood feeding. For blood feeding arthropods, including sand flies, blood meal digestion requires the secretion of inhibitory molecules, such as Kazal-type serine proteinase inhibitors that are involved in preventing the blood from coagulating within the mouthparts and the midgut. Previous studies have identified such molecules in mosquitoes, ticks, and triatomine bugs. Following studies of the midgut transcriptome of Phlebotomus papatasi, the principal vector of Leishmania major, two non-classical Kazal-type serine proteinase inhibitors were identified (PpKzl1 and PpKzl2). We are interested in the role of these proteins as inhibitors of coagulation cascades, in addition to their potential effects on blood digestion in P. papatasi. Ppkzl1 is similar to thrombin and trypsin inhibitors in triatomines and mosquitoes and Ppkzl2 is similar to Kazal-type inhibitors in mosquitoes with unknown function. Analyses of expression profiles indicated that although both transcripts are expressed prior to blood feeding in the midgut of P. papatasi they are tightly regulated by the blood meal. Reverse genetics studies using RNAi-targeted knockdown of PpKzl1 and PpKzl2 by dsRNA injection did not result in a detectable effect on mRNA expression levels. Thus, we expressed a recombinant PpKzl2 in a mammalian expression system (CHO-S free style cells) that was applied to in vitro studies to assess activity against various serine proteinases. Recombinant PpKzl2 inhibited chymotrypsin at nanomolar levels and also inhibited thrombin and trypsin at micromolar levels, suggesting that native PpKzl2 is an active serine proteinase inhibitor and may regulate digestive enzymes and thrombin in the midgut. Leishmania development within the sand fly midgut is faced with several barriers that can severely impact the parasites. For transmission to occur, parasites must be able to overcome these barriers including digestive proteinases, escape from the peritrophic matrix, and midgut attachment. Early stages of Leishmania are susceptible to killing by digestive proteinases in the sand fly midgut. Thus, targeting serine proteinase inhibitors may provide a new strategy to prevent transmission of Leishmania.

Abstract not available

Three protease inhibitor-like proteins (PILPs) identified from Bungarus multicinctus genome are structurally homologous with Kunitz-type proteinase inhibitor. The goal of the present study is to explore whether PILPs exhibit an inhibitory action on matrix metalloproteinase 2 (MMP-2) activity. Unlike PILP-1 and PILP-2, PILP-3 was found to inhibit MMP-2 activity as evidenced by specific substrate assay. Moreover, in vitro migration and invasion assays, and wound-healing assay showed that PILP-3 suppressed the migration and invasion of human neuroblastoma SK-N-SH cells. Pull-down assay and dot blotting-binding assay proved an interaction between PILP-3 and MMP-2. Nevertheless, PILP-3 did not affect either expression or secretion of MMP-2 in SK-N-SH cells. In terms of highly structural similarity between PILP-2 and PILP-3, two chimeric mutants in which amino acids at N-terminus and C-terminus of PILP-3 were substituted by those of PILP-2 were prepared. In contrast to N-terminus chimera, C-terminus mutant of PILP-3 was unable to inhibit MMP-2 activity and showed a reduction in binding with MMP-2. Taken together, our data suggest that PILP-3 may be a useful template for rational designing pharmaceutical agent in inhibiting MMP-2 activity.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This systematic review and meta-analysis tries to determine whether there is an association between the use of protease inhibitors (PIs) and the incidence of diabetes mellitus (DM) and/or metabolic syndrome (MS) in HIV-infected patients. A systematic literature search was performed using MEDLINE/PubMed, CENTRAL, LILACS, and EMBASE. Included articles were observational studies published on or prior to November 2015 that met specific inclusion criteria. Pooled relative risks (RRs) and hazard ratios (HRs) were calculated. Nine articles met the inclusion criteria, describing 13,742 HIV patients. Use of PIs was associated with the development of MS (RR: 2.11; 95% CI 1.28–3.48; p-value 0.003). No association between the use of PIs and development of DM was found: the HR for the incidence of DM among patients using PIs was 1.23 (95% CI 0.66–2.30; p-value: 0.51) and the RR was 1.25 (95% CI 0.99–1.58; p-value 0.06). Use of PIs in HIV-infected patients is associated with an increased risk of MS. No evidence of an increased risk of DM was found. However, because MS is a precursor to DM, it is possible that studies with a longer follow-up duration are needed in order to detect an association between PI use and onset of DM. / First, we would like to thank our families for all their support. Second, we would like to thank the Universidad Peruana de Ciencias Aplicadas, the Health Sciences Department, and the School of Medicine for their support and for all the tools they have provided throughout this process. Finally, we want to thanks to Dr Gwenyth O. Lee and Dr Daniela E. Kirwan for their comments. / Revisión por pares

Activated neutrophils release a neutrophil serine proteinase (NSP) called Proteinase 3 (PR3). In granulomatosis with polyangiitis (GPA), an autoimmune vasculitis, enhanced PR3 release results in endothelial damage. Serine proteinase inhibitors (serpins) such as α-1 proteinase inhibitor (API) inhibit NSPs through the serpin’s reactive center loop (RCL). However, API is known to bind PR3 with a low specificity, compared to its main inhibitory target Human Neutrophil Elastase (HNE). The current treatment for GPA is immunosuppression, which leaves patients immunocompromised. Thus, the overall aim of this study was to engineer an API variant with a higher specificity to PR3 than HNE, which could serve as a possible novel therapeutic strategy for GPA. We created an API expression library, hypervariable at RCL residues A355-I356-P357-M358-S359, and expressed it in a T7 bacteriophage display system. This phage library was then biopanned for PR3 binding. Two conditions were used for each round of biopanning: experimental, with PR3, and the negative control, without PR3. The library was biopanned for a total of five consecutive rounds, with the product of one screen serving as the starting material for the next. A bacterial mass lysate screen was also employed to further probe the library with PR3. The phage-display and bacterial lysate screens resulted in the selection of two novel variants API-DA (D357/A358) and API-N (N359). Serpin-proteinase gel complexing assays indicated that API-N formed complex with PR3 similar to API-WT (wild-type), while API-DA was mainly cleaved as a substrate. There was no significant difference between the second order rate constants of API-N and API-WT reactions with PR3. Rate constants for API-DA binding to PR3 or for API-HNE reactions were not completed due to novel coronavirus (COVID-19) restrictions. However, this project successfully demonstrated the ability to screen a hypervariable API phage library with PR3, yielding two new novel API variants. / Thesis / Master of Science in Medical Sciences (MSMS) / When harmful substances enter our body such as bacteria or viruses, we have ways of protecting ourselves from them. One of those ways is through a cell called the neutrophil. This is an immune cell that can release “fighting tools” into our blood to combat the harm. Some of these tools are called proteins. One of those proteins is Proteinase 3. However, sometimes our neutrophils can be activated without the presence of viruses or bacteria by products made in our bodies called autoantibodies. When this happens, too many of the “fighting tool” Proteinase 3 is released leading to damage to the tubes or vessels that our blood flows through. This project aimed to find a new possible way to stop these extra fighting tools from doing harm to our body. We did this by creating a library of different proteins that can stop Proteinase 3 once it is released by the neutrophil.

Introdução: As proteinases tem um papel importante no desenvolvimento, na destruição tecidual e na produção de muco causada pela DPOC. O inibidor de proteinase de origem vegetal Enterolobium contortisiliquum Tripsin Inhibitor (EcTI) inibe tanto as proteinases da classe serina quanto da classe cisteína. Objetivos: Avaliar os efeitos do tratamento com EcTI nas alterações pulmonares induzidas pela elastase em camundongos. Métodos: Camundongos C57Bl6 receberam elastase via intratraqueal (50 uL/animal, grupo ELA) ou salina (grupo SAL). Os camundongos foram tratados com EcTI (2mg/kg) nos dias 1, 15 e 21 após a instilação de elastase (grupo ELA-EcTI) ou salina (grupo SAL-EcTI). No dia 28 do protocolo, os animais foram anestesiados, a mecânica pulmonar foi medida e o óxido nítrico exalado coletado. Posteriormente, foi realizado o lavado broncoalveolar e os pulmões foram removidos para a preparação de lâminas de histoquímica e imunohistoquímica. Por meio de morfometria analisamos o número de células positivas para neutrófilos, TNF-alfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS assim como a fração de volume de 8-iso-PGF2alfa, fibras colágenas e elásticas, nos septos alveolares e nas vias aéreas. Também foram avaliados o número de células positivas para macrófagos nos septos alveolares e MUC5ac nas vias aéreas. Resultados: O inibidor de proteinase EcTI reduziu as alterações de mecânica pulmonar (Ers, Htis e Raw), destruição do septo alveolar (Lm) e o número de células no lavado broncoalveolar (células totais, macrófagos, neutrófilos, linfócitos e eosinógilos) induzidos pela elastase. Em relação a resposta inflamatória, o EcTI reduziu o número de neutrófilos e de células TNFalfa positivas no septo alveolar e nas vias aéreas além de reduzir o número de macrófagos no septo alveolar. Considerando o remodelamento de matriz extracelular, o inibidor de proteinase atenuou a fração de volume de fibras colágenas e o número de células MMP-9 e MMP-12 positivas nos septos alveolares e nas vias aéreas. Além disso, nas vias aéreas ocorreu uma atenuação da fração de volume de fibras elásticas, e nos septos alveolares uma atenuação da quantidade de células que expressam TIMP-1. Em relação a resposta de estresse oxidativo, o EcTI reduziu a fração de volume de isoprostano e o número de células iNOS e eNOS positivas tanto nos septos alveolares quanto nas vias aéreas. O EcTI também reduziu o número de células MUC5ac positivas nas vias aéreas. Conclusões: O tratamento como inibidor EcTI modulou a mecânica pulmonar e reduziu as alterações inflamatórias, de remodelamento e de estresse oxidativo induzidas pela elastase intratraqueal. Embora sejam necessários mais estudos para elucidar os mecanismos envolvidos neste processo, o inibidor de proteinase EcTI pode ser considerado como um potencial instrumento terapêutico para o tratamento da DPOC / Background: Proteinases play a key role on emphysema development, tissue destruction and mucus production. Enterolobium contortisiliquum Tripsin Inhibitor (EcTI) is a proteinase inhibitor from plant that neutralizes serine and cysteine proteinases. Aims: To evaluated the effects of the EcTI treatment in pulmonary alterations induced by elastase in mice. Methods: C57Bl6 mice received elastase intratracheally (50 uL/animal, ELA group) or saline (SAL group). Afterwards, mice were treated with EcTI (2 mg/kg) at days 1, 15 and 21 after elastase instillation (ELA-EcTI group). Control group received saline and EcTI using the same protocol (SAL-EcTI group). At day 28, mice were anesthetized, respiratory mechanics were collected, and exhaled nitric oxide were analyzed. Afterwards, broncoalveolar lavage fluid was obtained and lungs were removed to perform histochemistry and immunohistochemistry stains. By morphometry, the number of neutrophils, TNF-alfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS positive cells as well as the volume proportion of 8-iso-PGF2alfa, collagen and elastic fibers content in alveolar septum and airways walls were performed. In airways walls, we also analyzed the number of MUC-5 positive cells and the number of macrophages. Results: The proteinase inhibitor EcTI was able to reduce the pulmonary mechanical alterations (Ers, Htis and Raw), alveolar septum disruption (Lm) and the BAL cell count (total cells, macrophages, neutrophils, lymphocytes and eosinophils) induced by elastase. Regarding the inflammatory response, EcTI also reduced the number of neutrophils and TNFalfa positive cells in both alveolar septum and airway walls, and also reduced the number of macrophages in alveolar septum. Considering the extracellular matrix remodeling, the proteinase inhibitor attenuated the volume fraction of collagen fibers, MMP-9 and MMP-12 positive cells in both alveolar septum and airway walls. Besides, in airway there were attenuation in the volume fraction of elastic fibers, and in the alveolar septa a decrease of the amount of the cells expressing TIMP-1. Regarding the oxidative stress response, EcTI reduced the volume fraction of isoprostane and the number of iNOS and eNOS positive cells in both airways walls and alveolar septa, Finally, EcTI reduced the number of MUC5ac positive cells in airway walls. Conclusions: The treatment with EcTI modulated lung mechanics and reduced inflammatory, remodeling and oxidative stress alterations induced by elastase. Although more studies need to be performed to elucidate the mechanisms involved in this process, we may considerate EcTI as a potential therapeutic tool for COPD management

Introdução: As proteinases tem um papel importante no desenvolvimento, na destruição tecidual e na produção de muco causada pela DPOC. O inibidor de proteinase de origem vegetal Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) inibe tanto as proteinases da classe serina quanto da classe cisteína. Objetivos: Deste modo consideramos relevante estudar os efeitos do tratamento com BbCI nas alterações pulmonares induzidas pela elastase em camundongos. Métodos: Camundongos C57Bl6 receberam elastase via intratraqueal (50 uL/animal, grupo ELA) ou salina (grupo SAL). Os camundongos foram tratados com BbCI (2mg/kg) nos dias 1, 15 e 21 após a instilação de elastase (grupo ELABC) ou salina (grupo SALBC). No dia 28 do protocolo, os animais foram anestesiados, a mecânica pulmonar foi medida e o óxido nítrico exalado coletado. Posteriormente, foi realizado o lavado broncoalveolar e os pulmões foram removidos para a preparação de lâminas de histoquímica e imunohistoquímica. Por meio de morfometria analisamos o número de células positivas para neutrófilos, TNF-alfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS assim como a fração de volume de 8-iso-PGF2alfa, fibras colágenas e elásticas, nos septos alveolares e nas vias aéreas. Também foram avaliados o número de células positivas para macrófagos nos septos alveolares e MUC5ac nas vias aéreas. Resultados: O inibidor de proteinase Tese de Doutorado Rafael Almeida-Reis BbCI reduziu as alterações de mecânica pulmonar (Ers, Htis e Raw), destruição do septo alveolar (Lm) e o número de células no lavado broncoalveolar (células totais, macrófagos e neutrófilos) induzidos pela elastase. Em relação a resposta inflamatória, o BbCI reduziu o número de neutrófilos e de células TNFalfa positivas no septo alveolar e nas vias aéreas além de reduzir o número de macrófagos no septo alveolar. Considerando o remodelamento de matriz extracelular, o inibidor de proteinase atenuou a fração de volume de fibras elásticas e colágenas e o número de células MMP- 9 e MMP-12 positivas nos septos alveolares e nas vias aéreas. Em relação a resposta de estresse oxidativo, o BbCI reduziu a fração de volume de isoprostano nas vias aéreas e o número de células iNOS positivas tanto nos septos alveolares quanto nas vias aéreas. O BbCI também reduziu o número de células MUC5ac positivas nas vias aéreas. Conclusões: O tratamento como inibidor BbCI modulou a mecânica pulmonar e reduziu as alterações inflamatórias, de remodelamento e de estresse oxidativo induzidas pela elastase intratraqueal. Embora sejam necessários mais estudos para elucidar os mecanismos envolvidos neste processo, o inibidor de proteinase BbCI pode ser considerado como um potencial instrumento terapêutico para o tratamento da DPOC / Background: Proteinases play a key role on emphysema development, tissue destruction and mucus production. Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a proteinase inhibitor from plant that neutralizes serine and cysteine proteinases. The present study evaluated the effects of the BbCI treatment in pulmonary alterations induced by elastase in mice. Methods: C57Bl6 mice received elastase intratracheally (50 uL/animal, ELA group) or saline (SAL group). Afterwards, mice were treated with BbCI (2 mg/kg) at days 1, 15 and 21 after elastase instillation (ELABC group). Control group received saline and BbCI using the same protocol (SALBC group). At day 28, mice were anesthetized, respiratory mechanics were collected, and exhaled nitric oxide were analyzed. Afterwards, broncoalveolar lavage fluid was obtained and lungs were removed to perform histochemistry and immunohistochemistry stains. By morphometry, the number of neutrophils, TNFalfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS positive cells as well as the volume proportion of 8-iso-PGF2alfa, collagen and elastic fibers content in alveolar septum and airways walls were performed. In airways walls, we also analyzed the number of MUC-5 positive cells and the number of macrophages. Results: The proteinase inhibitor BbCI was able to reduce the pulmonary mechanical alterations (Ers, Htis and Raw), alveolar septum disruption (Lm) and the BAL cell count (total cells, macrophages and neutrophils) induced by elastase. Regarding the Tese de Doutorado Rafael Almeida-Reis inflammatory response, BbCI also reduced the number of neutrophils and TNFalfa positive cells in both alveolar septum and airway walls, and also reduced the number of macrophages in alveolar septum. Considering the extracellular matrix remodeling, the proteinase inhibitor attenuated the volume fraction of elastic and collagen fibers, MMP-9 and MMP-12 positive cells in both alveolar septum and airway walls. Regarding the oxidative stress response, BbCI reduced the volume fraction of isoprostane in airways and the number of iNOS positive cells in both airways walls and alveolar septum. Finally, BbCI reduced the number of MUC5ac positive cells in airway walls. Conclusions: The treatment with BbCI modulated lung mechanics and reduced inflammatory, remodeling and oxidative stress alterations induced by elastase. Although more studies need to be performed to elucidate the mechanisms involved in this process, but we may considerate BbCI as a potential therapeutic tool for COPD management

Introdução: As proteinases tem um papel importante no desenvolvimento, na destruição tecidual e na produção de muco causada pela DPOC. O inibidor de proteinase de origem vegetal Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) inibe tanto as proteinases da classe serina quanto da classe cisteína. Objetivos: Deste modo consideramos relevante estudar os efeitos do tratamento com BbCI nas alterações pulmonares induzidas pela elastase em camundongos. Métodos: Camundongos C57Bl6 receberam elastase via intratraqueal (50 uL/animal, grupo ELA) ou salina (grupo SAL). Os camundongos foram tratados com BbCI (2mg/kg) nos dias 1, 15 e 21 após a instilação de elastase (grupo ELABC) ou salina (grupo SALBC). No dia 28 do protocolo, os animais foram anestesiados, a mecânica pulmonar foi medida e o óxido nítrico exalado coletado. Posteriormente, foi realizado o lavado broncoalveolar e os pulmões foram removidos para a preparação de lâminas de histoquímica e imunohistoquímica. Por meio de morfometria analisamos o número de células positivas para neutrófilos, TNF-alfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS assim como a fração de volume de 8-iso-PGF2alfa, fibras colágenas e elásticas, nos septos alveolares e nas vias aéreas. Também foram avaliados o número de células positivas para macrófagos nos septos alveolares e MUC5ac nas vias aéreas. Resultados: O inibidor de proteinase Tese de Doutorado Rafael Almeida-Reis BbCI reduziu as alterações de mecânica pulmonar (Ers, Htis e Raw), destruição do septo alveolar (Lm) e o número de células no lavado broncoalveolar (células totais, macrófagos e neutrófilos) induzidos pela elastase. Em relação a resposta inflamatória, o BbCI reduziu o número de neutrófilos e de células TNFalfa positivas no septo alveolar e nas vias aéreas além de reduzir o número de macrófagos no septo alveolar. Considerando o remodelamento de matriz extracelular, o inibidor de proteinase atenuou a fração de volume de fibras elásticas e colágenas e o número de células MMP- 9 e MMP-12 positivas nos septos alveolares e nas vias aéreas. Em relação a resposta de estresse oxidativo, o BbCI reduziu a fração de volume de isoprostano nas vias aéreas e o número de células iNOS positivas tanto nos septos alveolares quanto nas vias aéreas. O BbCI também reduziu o número de células MUC5ac positivas nas vias aéreas. Conclusões: O tratamento como inibidor BbCI modulou a mecânica pulmonar e reduziu as alterações inflamatórias, de remodelamento e de estresse oxidativo induzidas pela elastase intratraqueal. Embora sejam necessários mais estudos para elucidar os mecanismos envolvidos neste processo, o inibidor de proteinase BbCI pode ser considerado como um potencial instrumento terapêutico para o tratamento da DPOC / Background: Proteinases play a key role on emphysema development, tissue destruction and mucus production. Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a proteinase inhibitor from plant that neutralizes serine and cysteine proteinases. The present study evaluated the effects of the BbCI treatment in pulmonary alterations induced by elastase in mice. Methods: C57Bl6 mice received elastase intratracheally (50 uL/animal, ELA group) or saline (SAL group). Afterwards, mice were treated with BbCI (2 mg/kg) at days 1, 15 and 21 after elastase instillation (ELABC group). Control group received saline and BbCI using the same protocol (SALBC group). At day 28, mice were anesthetized, respiratory mechanics were collected, and exhaled nitric oxide were analyzed. Afterwards, broncoalveolar lavage fluid was obtained and lungs were removed to perform histochemistry and immunohistochemistry stains. By morphometry, the number of neutrophils, TNFalfa, MMP-9, MMP-12, TIMP-1, iNOS, eNOS positive cells as well as the volume proportion of 8-iso-PGF2alfa, collagen and elastic fibers content in alveolar septum and airways walls were performed. In airways walls, we also analyzed the number of MUC-5 positive cells and the number of macrophages. Results: The proteinase inhibitor BbCI was able to reduce the pulmonary mechanical alterations (Ers, Htis and Raw), alveolar septum disruption (Lm) and the BAL cell count (total cells, macrophages and neutrophils) induced by elastase. Regarding the Tese de Doutorado Rafael Almeida-Reis inflammatory response, BbCI also reduced the number of neutrophils and TNFalfa positive cells in both alveolar septum and airway walls, and also reduced the number of macrophages in alveolar septum. Considering the extracellular matrix remodeling, the proteinase inhibitor attenuated the volume fraction of elastic and collagen fibers, MMP-9 and MMP-12 positive cells in both alveolar septum and airway walls. Regarding the oxidative stress response, BbCI reduced the volume fraction of isoprostane in airways and the number of iNOS positive cells in both airways walls and alveolar septum. Finally, BbCI reduced the number of MUC5ac positive cells in airway walls. Conclusions: The treatment with BbCI modulated lung mechanics and reduced inflammatory, remodeling and oxidative stress alterations induced by elastase. Although more studies need to be performed to elucidate the mechanisms involved in this process, but we may considerate BbCI as a potential therapeutic tool for COPD management