ROGERIO PAZETTI
Projetos de Pesquisa
Unidades Organizacionais
LIM/61 - Laboratório de Pesquisa em Cirurgia Torácica, Hospital das Clínicas, Faculdade de Medicina
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article 5 Citação(ões) na Scopus An experimental rat model of ex vivo lung perfusion for the assessment of lungs after prostacyclin administration: inhaled versus parenteral routes(2011) CARDOSO, Paulo Francisco Guerreiro; PAZETTI, Rogerio; MORIYA, Henrique Takachi; PEGO-FERNANDES, Paulo Manuel; ALMEIDA, Francine Maria de; CORREIA, Aristides Tadeu; FECHINI, Karina; JATENE, Fabio BiscegliObjective: To present a model of prostaglandin I(2) (PGI(2)) administration (inhaled vs. parenteral) and to assess the functional performance of the lungs in an ex vivo lung perfusion system. Methods: Forty Wistar rats were anesthetized and placed on mechanical ventilation followed by median sterno-laparotomy and anticoagulation. The main pulmonary artery was cannulated. All animals were maintained on mechanical ventilation and were randomized into four groups (10 rats/group): inhaled saline (IS); parenteral saline (PS); inhaled PGI(2) (IPGI(2)); and parenteral PGI(2) (PPGI(2)). The dose of PGI(2) used in the IPGI(2) and PPGI(2) groups was 20 and 10 mu g/kg. respectively. The heart-lung blocks were submitted to antegrade perfusion with a low potassium and dextran solution via the pulmonary artery, followed by en bloc extraction and storage at 4 degrees C for 6 h. The heart-lung blocks were then ventilated and perfused in an ex vivo lung perfusion system for 50 min. Respiratory mechanics, hemodynamics, and gas exchange were assessed. Results: Mean pulmonary artery pressure following nebulization decreased in all groups (p < 0.001), with no significant differences among the groups. During the ex vivo perfusion, respiratory mechanics did not differ among the groups, although relative oxygenation capacity decreased significantly in the IS and PS groups (p = 0.04), whereas mean pulmonary artery pressure increased significantly in the IS group. Conclusions: The experimental model of inhaled PGI(2) administration during lung extraction is feasible and reliable. During reperfusion, hemodynamics and gas exchange trended toward better performance with the use of PGI(2) than that with the use of saline.- An in vivo image acquisition system for the evaluation of tracheal mechanics in rats(2020) VALENGA, Marcelo Henrique; VITORASSO, Renato de Lima; RODRIGUES, Thiago Guimaraes; PAZETTI, Rogerio; CARDOSO, Paulo Francisco Guerreiro; MORIYA, Henrique Takachi; AOKI, Fabio GavaMechanical evaluation of tracheal grafts is of great relevance for transplant research. Although there are some publications demonstrating different techniques of tracheal mechanical evaluation, there is still no definitive or preferred protocol available. Here, we present a simple image processing acquisition system that can be used for in vivo experiments. Six male Wistar rats were submitted to orotracheal intubation and a longitudinal incision was made to expose the trachea. Images of tracheae were acquired from a video camera in different scenarios of bronchoconstriction using methacholine (MCh) (Basal, PBS, MCh 30 mu g/kg, MCh 300 mu g/kg, and postmetabolized) during imposed-inspiration and imposed-expiration. The area variation ratio (the ratio between areas during expiration vs. inspiration) was 1.1x for the Basal group, while the ratio for MCh 300 mu g/kg was 6.5x. The area variation of imaged tracheae was statistically significant at the dose of MCh 300 mu g/kg for imposed-inspiration versus imposed-expiration (P = .002). Likewise, elastance data of respiratory mechanics indicated a statistically significant difference at the dose of MCh 300 mu g/kg for imposed-inspiration versus imposed-expiration (P = .026). Our image processing analysis protocol presented corresponding behavior when compared to mechanical parameters of the respiratory system. In addition, our image acquisition system was able to highlight the differences between imposed-inspiration and imposed-expiration. Image analysis of the tracheal area variation seems to be in agreement with the elastance of the respiratory system. Taken together, these observations may help future studies of tracheal transplantation for in situ assessment of graft patency.
- Comparing the Performance of Rat Lungs Preserved for 6 or 12 Hours After Perfusion With Low-Potassium Dextran or Histidine-Tryptophan-Ketoglutarate(2011) SIMOES, E. A.; PEGO-FERNANDES, P. M.; CARDOSO, P. F. G.; PAZETTI, R.; WEREBE, E.; BRAGA, K. A. de Oliveira; MENEZES, A.; NEPOMUCENO, N.; SOARES, P. R. O.; CORREIA, A. T.; JATENE, F. B.Introduction. In lung transplantation, graft dysfunction is a frequent cause of mortality; the etiopathogenesis is related to ischemia-reperfusion injury. We sought to compare the lung performance of rats after reperfusion after presentation with 3 solutions at 2 ischemia times. Methods. We randomized 60 male Wistar rats to undergo anterograde perfusion via the pulmonary artery with low-potassium dextran (LPD), histidine tryptophan ketoglutarate (HTK), or saline. After extraction, the heart lung blocks were preserved in a solution at hypothermia for 6 or 12 hours before perfusion with homologous blood for 60 minutes using ex vivo system Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus). Respiratory mechanics, pulmonary weight, pulmonary artery pressure (PAP), and relative lung oxygenation capacity (ROC) measurements were obtained every 10 minutes. Results. Comparing tidal volume (TV), compliance, resistance, ROC, PAP, and pulmonary weight the LPD, HTK, and saline group did not differ at 6 and 12 hours. The TV was higher in the lungs with 6-hour ischemia in the LPD, HTK, and saline groups. Compliance was higher in the lungs with 6-hour ischemia in the LPD and saline groups. There were no differences in ROC values comparing lungs with 6- versus 12-hour ischemia in the LPD group. A significant difference was observed between lungs in the HTK and saline groups. Resistance was higher in the lungs with 12-hour ischemia among the LPD, HTK, and saline groups. There was a gradual weight increase in the lungs, particularly those undergoing 12-hour ischemia, despite the absence of a significant difference between groups. Conclusion. Rat lungs perfused with LPD and HTK preservation solutions showed similar reperfusion performances in this ex-vivo perfusion model.
- Modelo experimental de perfusão pulmonar ex vivo em ratos: avaliação histopatológica e de apoptose celular em pulmões preservados com solução de baixo potássio dextrana vs. solução histidina-triptofano-cetoglutarato(2012) SIMOES, Edson Azevedo; CARDOSO, Paulo Francisco Guerreiro; PEGO-FERNANDES, Paulo Manuel; CANZIAN, Mauro; PAZETTI, Rogerio; BRAGA, Karina Andriguetti de Oliveira; NEPOMUCENO, Natalia Aparecida; JATENE, Fabio BiscegliObjective: To compare histopathological findings and the degree of apoptosis among rat lungs preserved with low-potassium dextran (LPD) solution, histidine-tryptophan-ketoglutarate (HTK) solution, or normal saline (NS) at two ischemia periods (6 h and 12 h) using an experimental rat model of ex vivo lung perfusion. Methods: Sixty Wistar rats were anesthetized, randomized, and submitted to antegrade perfusion via pulmonary artery with one of the preservation solutions. Following en bloc extraction, the heart-lung blocks were preserved for 6 h or 12 h at 4 degrees C and then reperfused with homologous blood for 60 min in an ex vivo lung perfusion system. At the end of the reperfusion, fragments of the middle lobe were extracted and processed for histopathological examination. The parameters evaluated were congestion, alveolar edema, alveolar hemorrhage, inflammatory infiltrate, and interstitial infiltrate. The degree of apoptosis was assessed using the TdT-mediated dUTP nick end labeling method. Results: The histopathological examination showed that all of the lungs preserved with NS presented alveolar edema after 12 h of ischemia. There were no statistically significant differences among the groups in terms of the degree of apoptosis. Conclusions: In this study, the histopathological and apoptosis findings were similar with the use of either LPD or HTK solutions, whereas the occurrence of edema was significantly more common with the use of NS.
- Assessment of the mechanics of a tissue-engineered rat trachea in an image-processing environment(2014) SILVA, Thiago Henrique Gomes da; PAZETTI, Rogerio; AOKI, Fabio Gava; CARDOSO, Paulo Francisco Guerreiro; VALENGA, Marcelo Henrique; DEFFUNE, Elenice; EVARISTO, Thaiane; PEGO-FERNANDES, Paulo Manuel; MORIYA, Henrique TakachiOBJECTIVES: Despite the recent success regarding the transplantation of tissue-engineered airways, the mechanical properties of these grafts are not well understood. Mechanical assessment of a tissue-engineered airway graft before implantation may be used in the future as a predictor of function. The aim of this preliminary work was to develop a noninvasive image-processing environment for the assessment of airway mechanics. METHOD: Decellularized, recellularized and normal tracheas (groups DECEL, RECEL, and CONTROL, respectively) immersed in Krebs-Henseleit solution were ventilated by a small-animal ventilator connected to a Fleisch pneumotachograph and two pressure transducers (differential and gauge). A camera connected to a stereomicroscope captured images of the pulsation of the trachea before instillation of saline solution and after instillation of Krebs-Henseleit solution, followed by instillation with Krebs-Henseleit with methacholine 0.1 M (protocols A, K and KMCh, respectively). The data were post-processed with computer software and statistical comparisons between groups and protocols were performed. RESULTS: There were statistically significant variations in the image measurements of the medial region of the trachea between the groups (two-way analysis of variance [ANOVA], p < 0.01) and of the proximal region between the groups and protocols (two-way ANOVA, p < 0.01). CONCLUSIONS: The technique developed in this study is an innovative method for performing a mechanical assessment of engineered tracheal grafts that will enable evaluation of the viscoelastic properties of neo-tracheas prior to transplantation.
- Comparison of Celsior and Perfadex lung preservation solutions in rat lungs subjected to 6 and 12 hours of ischemia using an ex-vivo lung perfusion system(2012) MENEZES, Arteiro Queiroz; PEGO-FERNANDES, Paulo Manuel; CARDOSO, Paulo Francisco Guerreiro; BRAGA, Karina Andrighetti de Oliveira; NEPOMUCENO, Natalia Aparecida; PAZETTI, Rogerio; CORREIA, Aristides Tadeu; CANZIAN, Mauro; SANTIM, Jacqueline Klarosk; JATENE, Fabio BiscegliOBJECTIVE: This study evaluated the performance of lungs that were preserved with different solutions (Celsior, Perfadex or saline) in an ex vivo rat lung perfusion system. METHODS: Sixty Wistar rats were anesthetized, anticoagulated and randomized into three groups (n = 20). The rats were subjected to antegrade perfusion via the pulmonary artery with Perfadex, Celsior, or saline, followed by 6 or 12 hours of ischemia (4 degrees C, n = 10 in each group). Respiratory mechanics, gas exchange and hemodynamics were measured at 10-minute intervals during the reperfusion of heart-lung blocks in an ex vivo system (IL2-Isolated Perfused Rat or Guinea Pig Lung System, Harvard Apparatus, Holliston, Massachusetts, USA; Hugo Sachs Elektronik, Germany) for 60 minutes. The lungs were prepared for histopathology and evaluated for edema following reperfusion. Group comparisons were performed using ANOVA and the Kruskal-Wallis test with a 5% level of significance. RESULTS: Gas exchange was not significantly different between lungs perfused with either Perfadex or Celsior at the same ischemic times, but it was very low in lungs that were preserved with saline. Airway resistance was greater in the lungs that were preserved for 12 hours. Celsior lungs that were preserved for 6 and 12 hours exhibited lower airway resistance (p = 0.01) compared to Perfadex lungs. Pulmonary artery pressure was not different between the groups, and no significant differences in histopathology and apoptosis were observed between the groups. CONCLUSIONS: Lungs that were preserved with Celsior or Perfadex exhibited similar gas exchange and histopathological findings. Airway resistance was slightly lower in the Celsior-preserved lungs compared with the Perfadex-preserved lungs.
- Respiratory parameters have different patterns in imposed-inspiration and imposed-expiration within a closed pneumatic circuit in rats(2015) AOKI, F. G.; VALENGA, M. H.; RODRIGUES, T. G.; CARDOSO, P. F. G.; PAZETTI, R.; MORIYA, H. T.Computer-controlled research ventilators for small animals (SAV) are often used to assess the respiratory mechanics' parameters such as resistance and elastance of the respiratory system in animal models of disease. In commercially available SAVs, it is common to obtain such parameters with the forced oscillation of a given volume of air into respiratory system with a quasi-sinusoidal pattern in a closed pneumatic circuit (i.e. both the injection and the removal of gas during the piston movement). We hypothesized that obtaining the respiratory mechanical parameters with the linear single-compartment model (LSCM) during the forced inspiration and forced expiration (when calculated together) is not sufficient to explain the physiology of the respiratory system exposed to high doses of bronchial agonist. In order to verify this, male Wistar rats (n = 5) were anesthetized, orotracheally intubated, mechanically ventilated at 90bpm (or 1.5Hz) with a tidal volume of 10mL/kg, and a positive end-expiratory pressure (PEEP) was set at 3cmH(2)O. The ventilation was performed in a commercial mechanical ventilator (flexiVent, SCIREQ Inc., Canada) and the animals were infused with a saline solution (PBS), followed by 3 increasing doses (3, 30 and 300mg/mL) of the bronchial agonist methacholine (MCh). Respiratory parameters were calculated by the LSCM. Pressure and volume data, calibrated and corrected by a proprietary software, were analyzed using a computational routine. The full quasisinusoidal signal data was compared to inlet and outlet of air from the lungs separately. The data obtained showed that the difference among the three signals (i.e. whole signal, imposed-inspiration, and imposed-expiration) is pronounced at the higher dose (MCh 300mg/mL). Data from imposed-inspiration alone seem to better reflect the respiratory mechanics when a large dose of bronchial agonist is used.
- Comparison of Three Different Mathematical Models Applied to Respiratory Mechanics During Bronchoconstriction(2019) BARROS, Amanda N.; VITORASSO, Renato de L.; VALENGA, Marcelo H.; AOKI, Fabio Gava; RODRIGUES, Thiago Guimaraes; CARDOSO, Paulo F. G.; PAZETTI, Rogerio; MORIYA, Henrique T.The assessment of respiratory mechanics is usually made by mathematical models. The simplest and one of the most known models is the Linear Single-Compartment Model (LSCM). The main prerogative of LSCM is linearity. However, the respiratory system does not have a linear behavior under several circumstances and the objective of this work is to compare the LSCM with 2 nonlinear models. In order to fulfill these comparisons, 6 male Wistar rats were studied during bronchoconstriction. Using a commercial ventilator, the LSCM and two nonlinear variations of this model were applied during mechanical ventilation in basal and during two doses of methacholine (MCh) a bronchoconstrictor. The two nonlinear models were: (1) a volume-dependent single compartment model, which have a nonlinear term related to elastance; (2) a flow-dependent single compartment model, which have a nonlinear term related to resistance. This study evaluated the adjustment of models to the measured pressure value and the evaluation of these models was conducted using the F-ratio test, which is based in comparison of variances, and the Akaike criterion, that measures the difference between the model and the sample values. Through of the value of mean squared residual, the results indicate improvement at the approximation when we add the nonlinear terms in relation to the linear model, in most cases, mainly the volume-dependent single compartment model. And another result is that the Akaike criterion presented a more effective comparison during the evaluation than the F-ratio test.
- Comparison Between Perfadex and Locally Manufactured Low-Potassium Dextran Solution for Pulmonary Preservation in an Ex Vivo Isolated Lung Perfusion Model(2011) SOARES, P. R. O.; BRAGA, K. A. D. O.; NEPOMUCENO, N. A.; PAZETTI, R.; CORREIA, A. T.; CARDOSO, P. F. G.; BISCEGLIJATENE, F.; PEGO-FERNANDES, P. M.Introduction. Lung tranplantation, a consolidated treatment for end-stage lung disease, utilizes preservation solutions, such as low potassium dextran (LPD), to mitigate ischemia reperfusion injury. We sought the local development of LPD solutions in an attempt to facilitate access and enhance usage. We also sought to evaluate the effectiveness of a locally manufactured LPD solution in a rat model of ex vivo lung perfusion. Methods. We randomized the following groups \?\adult of male Wistar rats (n = 25 each): Perfadex (LPD; Vitro life, Sweden); locally manufactured LPD-glucose (LPDnac) (Farmoterapica, Brazil), and normal saline solution (SAL) with 3 ischemic times (6, 12, and 24 hours). The harvested heart lung blocks were flushed with solution at 4 C. After storage, the blocks were connected to an IL-2 Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus) and reperfused with homologous blood for 60 minutes. Respiratory mechanics, pulmonary artery pressure, perfusate blood gas analysis, and lung weight were measured at 10-minute intervals. Comparisons between groups and among ischemic times were performed using analysis of variance with a 5% level of significance. Results. Lungs preserved for 24 hours were nonviable and therefore excluded from the analysis. Those preserved for 6 hours showed better ventilatory mechanics when compared with 12 hours. The oxygenation capacity was not different between lungs flushed with LPD or LPDnac, regardless of the ischemic time. SAL lungs showed higher PCO(2) values than the other solutions. Lung weight increased over time during perfusion; however, there were no significant differences among the tested solutions (LPD, P = .23; LPDnac, P = .41; SAL, P = .26). We concluded that the LPDnac solution results in gas exchange were comparable to the original LPD (Perfadex); however ventilatory mechanics and edema formation were better with LPD, particularly among lungs undergoing 6 hours of cold ischemia.