Alternative solution for ex vivo lung perfusion, experimental study on donated human lungs non-accepted for transplantation

PURPOSE: To evaluate a new perfusate solution to be used for ex vivo lung perfusion. METHODS: Randomized experimental study using lungs from rejected brain-dead donors harvested and submitted to 1 hour of ex vivo lung perfusion (EVLP) using mainstream solution or the alternative. RESULTS: From 16 lungs blocs tested, we found no difference on weight after EVLP: Steen group (SG) = 1,097±526g; Alternative Perfusion Solution (APS) = 743±248g, p=0.163. Edema formation, assessed by Wet/dry weigh ratio, was statistically higher on the Alternative Perfusion Solution group (APS = 3.63 ± 1.26; SG = 2.06 ± 0.28; p = 0.009). No difference on PaO2 after EVLP (SG = 498±37.53mmHg; APS = 521±55.43mmHg, p=0.348, nor on histological analyses: pulmonary injury score: SG = 4.38±1.51; APS = 4.50±1.77, p=0.881; apoptotic cells count after perfusion: SG = 2.4 ± 2.0 cells/mm2; APS = 4.8 ± 6.9 cells/mm2; p = 0.361). CONCLUSION: The ex vivo lung perfusion using the alternative perfusion solution showed no functional or histological differences, except for a higher edema formation, from the EVLP using Steen Solution(r) on lungs from rejected brain-dead donors. .

Nova contribuição ao estudo do remodelamento ventricular e dos anéis valvares na cardiomiopatia dilatada: avaliação anátomo-histopatológica / New contribution to the study of ventricular remodeling and valve rings in dilated cardiomyopathy: anatomical and histological evaluation

Introdução: A cardiomiopatia dilatada idiopática (CMDId) é causadora de grande impacto, porém aspectos de sua fisiopatologia são desconhecidos. Objetivo: Avaliar aspectos anatomo-histológicos de corações com CMDId comparando-os a corações normais, com medidas perimetrais dos anéis atrioventriculares direito (AVD) e esquerdo (AVE) e dos ventrículos direito (VD) e esquerdo (VE) e a porcentagem de fibras colágenas e elásticas dos anéis. Métodos: Foram avaliados 13 corações de cadáveres portadores de CMDId e 13 corações normais, que foram dissecados mantendo-se os anéis atrioventriculares e a massa ventricular, com laminação em segmentos correspondentes a 20%, 50% e 80% da distância entre o sulco atrioventricular e o ápice ventricular. Os cortes foram submetidos à digitalização fotográfica, sendo comparadas as medidas. Os anéis foram dissecados, medidos e enviados ao laboratório de anatomia patológica, sendo realizadas colorações por meio de hematoxilina-eosina, picrossírius e resorcina fuccina oxidada. Resultados: Com relação aos ventrículos, no grupo CMDId ocorre dilatação nos segmentos apical, equatorial e basal. A medida do AVD foi maior no grupo CMDId, não havendo diferença no AVE entre os grupos. Com relação ao percentual de fibras colágenas, há diminuição no grupo CMDId em relação ao grupo normal. Com relação às fibras elásticas, não houve diferença entre os grupos. Conclusão: Ocorre alteração da geometria ventricular com dilatação no grupo CMDId. Na CMDId observou-se aumento no perímetro do AVD. Não se observou aumento do perímetro do AVE. Houve diminuição percentual na área total de colágeno tanto no AVD quanto no AVE em corações com CMDId. .

Introduction: Idiopathic dilated cardiomyopathy causes great impact but many aspects of its pathophysiology remain unknown. Objective: To evaluate anatomical and histological aspects of hearts with idiopathic dilated cardiomyopathy and compare them to a control group, evaluating the behavior of the perimeters of the atrioventricular rings and ventricles and to compare the percentage of collagen and elastic fibers of the atrioventricular rings. Methods: Thirteen hearts with cardiomyopathy and 13 normal hearts were analysed. They were dissected keeping the ventricular mass and atrioventricular rings, with lamination of segments 20%, 50% and 80% of the distance between the atrioventricular groove and the ventricular apex. The sections were subjected to photo scanning, with measurement of perimeters. The atrioventricular rings were dissected and measured digitally to evaluate their perimeters, later being sent to the pathology laboratory, and stained by hematoxylin-eosin, picrosirius and oxidized resorcin fuccin. Results: Regarding to ventricles, dilation occurs in all segments in the pathological group, and the right atrioventricular ring measurement was higher in idiopathic dilated cardiomyopathy group, with no difference in the left side. With respect to collagen, both sides had lower percentage of fibers in the pathological group. With respect to the elastic fibers, there was no difference between the groups. Conclusion: There is a change in ventricular geometry in cardiomyopathy group. The left atrioventricular ring does not dilate, in spite of the fact that in both ventricles there is lowering of collagen. .

Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall / Cardiomiopatia dilatada idiopática: estudo anatômico computadorizado da relação entre o septo e a parede livre do ventrículo esquerdo

Introduction: A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. Objective: To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. Methods: We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. Results: Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). Conclusion: In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the ...

Introdução: Uma das características da cardiomiopatia dilatada idiopática é a deformação da cavidade ventricular, a qual contribui para a disfunção sistólica. Poucos trabalhos julgam importante a avaliação dessa deformação ventricular levando em consideração regiões e segmentos do ventrículo, o que pode revelar detalhes importantes do processo de remodelamento, dando suporte a um melhor entendimento do seu papel no comprometimento funcional e ao surgimento de novas estratégias terapêuticas. Objetivo: Verificar se, em regiões diferentes, o aumento do perímetro transversal da câmara ventricular esquerda na cardiomiopatia dilatada idiopática ocorre de maneira proporcional entre o segmento septal e o não septal (parede livre). Métodos: Foi realizado um estudo anatômico com 28 corações adultos. Um grupo foi constituído por 18 corações com cardiomiopatia dilatada idiopática e outro grupo com 10 corações normais. Em três regiões diferentes (base, equador e ápice), o perímetro interno transversal do ventrículo esquerdo foi dividido em dois segmentos: septal e não septal. Foi criado um índice de proporcionalidade entre esses segmentos. Em seguida verificou-se se esse índice era o mesmo entre os grupos. Resultados: Entre corações normais e portadores de cardiomiopatia dilatada idiopática, o índice de proporcionalidade entre os dois segmentos (septal e não septal) não apresentou diferença significativa nas três regiões analisadas. Conclusão: Na cardiomiopatia dilatada idiopática, a dilatação transversal do septo é proporcional à dilatação da parede livre nas regiões basal, equatorial e apical da câmara ventricular esquerda. .

Biocompatibility of a new device of self-expandable covered and non-covered tracheal stent: comparative study in rats

PURPOSE: To investigate the compatibility of a new model of self-expandable tracheal stent in rats. METHODS: A new device of polyurethane covered and non - covered stent was placed in the trachea of Wistar rats. Animals were distributed in two groups: the polyurethane covered and non-covered group. Macroscopic parameters included position within the tracheal lumen, adherence to the mucosa, degree of dilatation, permeability and internal diameter. Microscopic findings evaluated were: incorporation, inflammatory activity, granulation tissue and epithelial revetment injuries. The observation follow-up was six weeks. All parameters were quantified based on determined score values. Incorporation of the stents was evaluated based on the observation if the stent was fixed into the trachea or if it could be removed. Degree of dilatation was performed by external diameter measurements. Granulation tissue was evaluated by measurements of height of the tissue growing into the tracheal lumen. RESULTS: 100% of non-covered stents had total attachment to mucosa and 100% of polyurethane covered type had adherence only. Regarding dilatation, granulation tissue, inflammatory activity and internal diameter measurements, there were no significant differences between the groups. Pathological tracheal wall injuries were present in both groups. CONCLUSION: Both models of stent demonstrated biocompatibility with the trachea. Rats are suitable for an experimental model of tracheal stent study.

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

OBJECTIVE: 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 (4ºC, 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.

The effects on mucociliary clearance of prednisone associated with bronchial section

OBJECTIVE: Infections have been and remain the major cause of morbidity and mortality after lung transplantation. Because mucociliary clearance plays an important role in human defense mechanisms, the influence of drugs on the mucociliary epithelium of patients undergoing lung transplantation must be examined. Prednisone is the most important corticosteroid used after lung transplantation. The aim of this study was to evaluate the effects of bronchial transection and prednisone therapy on mucociliary clearance. METHODS: A total of 120 rats were assigned to 4 groups according to surgical procedure or drug therapy: prednisone therapy (1.25 mg/kg/day); bronchial section and anastomosis + prednisone therapy (1.25 mg/kg/day); bronchial section + saline solution (2 ml/day); and saline solution (2 ml/day). After 7, 15, or 30 days, the animals were sacrificed, and the lungs were removed from the thoracic cavity. The in situ mucociliary transport velocity, ciliary beat frequency and in vitro mucus transportability were evaluated. RESULTS: Animals undergoing bronchial section surgery and anastomosis had a significant decrease in the ciliary beat frequency and mucociliary transport velocity 7 and 15 days after surgery (p<0.001). These parameters were normalized 30 days after the surgical procedure. Prednisone improved mucous transportability in the animals undergoing bronchial section and anastomosis at 15 and 30 days (p<0.05). CONCLUSION: Bronchial section and anastomosis decrease mucociliary clearance in the early postoperative period. Prednisone therapy improves mucus transportability in animals undergoing bronchial section and anastomosis.

Modelo experimental de perfusão pulmonar ex vivo em ratos: avaliação de desempenho de pulmões submetidos à administração de prostaciclina inalada versus parenteral / An experimental rat model of ex vivo lung perfusion for the assessment of lungs after prostacyclin administration: inhaled versus parenteral routes

OBJETIVO: Apresentar um modelo experimental de administração de prostaglandina I2 (PGI2) por via inalatória vs. parenteral e avaliar o desempenho funcional dos pulmões em um sistema de perfusão pulmonar ex vivo. MÉTODOS: Quarenta ratos Wistar foram anestesiados, ventilados, submetidos a laparotomia com ressecção do esterno e anticoagulados. O tronco da artéria pulmonar foi canulado. Todos os animais foram submetidos a ventilação mecânica. Os animais foram randomizados em quatro grupos (10 ratos/grupo): salina nebulizada (SN); salina parenteral (SP); PGI2 nebulizada (PGI2N); e PGI2 parenteral (PGI2P). A dose de PGI2 nos grupos PGI2N e PGI2P foi de 20 e 10 µg/kg, respectivamente. Os blocos cardiopulmonares foram submetidos in situ a perfusão anterógrada com solução de baixo potássio e dextrana a 4ºC via artéria pulmonar, extraídos em bloco e armazenados a 4ºC por 6 h. Os blocos foram ventilados e perfundidos em um sistema ex vivo por 50 min, sendo obtidas medidas de mecânica ventilatória, hemodinâmica e trocas gasosas. RESULTADOS: Houve redução da pressão arterial pulmonar média após a nebulização em todos os grupos (p < 0,001), sem diferença entre os grupos. Na perfusão ex vivo, a mecânica ventilatória não diferiu entre os grupos. Houve redução da capacidade relativa de oxigenação ao longo da perfusão nos grupos SN e SP (p = 0,04), e houve aumento significativo da pressão arterial pulmonar no grupo SN. CONCLUSÕES: O modelo experimental de administração de PGI2 na extração pulmonar é exequível e confiável. Na reperfusão, os resultados de hemodinâmica e de trocas gasosas demonstraram tendência a um melhor desempenho com o uso de PGI2 do que com solução salina.

OBJECTIVE:To present a model of prostaglandin I2 (PGI2) 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 PGI2 (IPGI2); and parenteral PGI2 (PPGI2). The dose of PGI2 used in the IPGI2 and PPGI2 groups was 20 and 10 µg/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 4ºC 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 PGI2 administration during lung extraction is feasible and reliable. During reperfusion, hemodynamics and gas exchange trended toward better performance with the use of PGI2 than that with the use of saline.

Effects of mycophenolate sodium on mucociliary clearance using a bronchial section and anastomosis rodent model

OBJECTIVE: To study the effects of mycophenolate sodium on mucociliary clearance. INTRODUCTION: Mycophenolate is one of the most commonly used immunosuppressive drugs in lung transplantation. Although its pharmacokinetic properties are well defined, its side effects on mucociliary clearance have not yet been studied. METHODS: Sixty rats were subjected to left bronchial section and anastomosis. The right bronchus was used as a control. After surgery, the rats were assigned to two groups based on whether they received saline solution (n = 30) or mycophenolate sodium (n = 30). After 7, 15, or 30 days of treatment, 10 animals from each group were sacrificed, and in vitro mucus transportability, in situ mucociliary transport velocity and ciliary beat frequency were measured. RESULTS: The analysis of mucus transportability revealed that neither mycophenolate nor bronchial section altered any transportability related property for up to 30 days of treatment after surgery (p>0.05). With regard to ciliary beat frequency, the operated left bronchi from the mycophenolate group showed a significant decrease on post-surgical day 30 (p = 0.003). In addition, we found a significant reduction in the in situ mucociliary transport velocity in the mycophenolate-treated group (p = 0.0001). DISCUSSION: These data add important information regarding mucociliary clearance dysfunction following mycophenolate therapy and suggest that mycophenolate might contribute to the high incidence of respiratory tract infections in lung transplant patients. Further studies are needed to investigate the combined action of mycophenolate with other immunosuppressive drugs and to establish methods to protect and recover mucociliary clearance, an important airway defense mechanism.

Influence of cyclosporine A on mucociliary system after lung transplantation in rats

PURPOSE: To investigate the function of the bronchial mucociliary system in transplanted rat lungs with and without the influence of immunosuppression. METHODS: Thirty-six rats underwent single-lung transplantation and were divided into two groups, one of which received cyclosporine treatment, and the control group which did not. Cyclosporine was administered subcutaneously in doses of 10 mg/kg daily. The rats were sacrificed 2, 15 or 30 days after transplantation. In situ bronchial mucociliary transport (MCT) and ciliary beat frequency (CBF) were determined proximal and distal to the bronchial anastomosis. RESULTS: Significant progressive improvement on MCT, proximal and distal to the anastomotic site, was also found in the cyclosporine-treated group at 15 and 30 days (p<0.01). No significant change in MCT was found in the control group. CBF behavior in the two groups. Histological analysis showed that rejection was significantly higher in the control group (p<0.05). CONCLUSION: Cyclosporine has a positive influence on bronchial mucociliary transport but not on CBF due to the effect of the rejection mechanism.

OBJETIVO: Investigar a função do sistema mucociliar em ratos transplantados sob a influência de imunossupressores. MÉTODOS: Trinta e seis ratos foram submetidos ao transplante pulmonar unilateral e divididos em dois grupos, onde um grupo foi tratado com ciclosporina e outro foi controle. Administrada ciclosporina por via subcutânea na dose de 10 mg/kg diariamente. Os ratos foram sacrificados 2, 15 e 30 dias após o transplante pulmonar. O transporte mucociliar brônquico (TMC) in situ e a freqüência de batimento ciliar (FBC) foram analisados na porção proximal e distal à anastomose brônquica. Realizada correlação dos achados com parâmetros gasométricos e histologia. RESULTADOS: Foi encontrada melhora progressiva e significante no TMC na região proximal e distal a anastomose no grupo que recebeu ciclosporina em 15 e 30 dias (p<0,01). Não houve diferença na FBC nos dois grupos estudados. A análise histológica mostrou que a rejeição foi significantemente maior no grupo controle (p<0,05). A oxigenação foi melhor nos animais que receberam a ciclosporina. CONCLUSÃO: A ciclosporina exerceu influência positiva no transporte mucociliar brônquico, provavelmente por sua ação imunossupressora.

Avaliação das alterações morfológicas cardíacas secundárias ao enfisema pulmonar: estudo experimental em ratos / Evaluation of the cardiac morphological alterations secondary to the pulmonary emphysema: experimental study in rats

OBJETIVO: Este trabalho tem como objetivo avaliar a ocorrência e as repercussões de enfisema pulmonar quimicamente induzido e as alterações morfológicas presentes em corações de ratos após sua indução, acompanhando sua progressão ao longo do tempo. MÉTODO: Foram avaliados 75 ratos divididos em dois grupos, papaína (N=50) e controle (N=25), submetidos à instilação intratraqueal de papaína e solução fisiológica, respectivamente. Os animais foram sacrificados 30, 60, 90, 120 ou 180 dias após a instilação. Foi realizada gasometria do sangue arterial, análise morfométrica dos pulmões e coração. RESULTADOS: A instilação de papaína produziu destruição do tecido alveolar, mimetizando alterações morfológicas encontradas no enfisema pulmonar, com diâmetro alveolar médio maior no grupo papaína em relação ao controle em todos os momentos avaliados (p<0,05). A espessura da parede do ventrículo direito e do septo interventricular não apresentou alterações macroscópicas significativas no período de até seis meses após a indução do enfisema. A cavidade do ventrículo direito apresentou dilatação, a partir de 120 dias após indução do enfisema, com área média superior aos respectivos controles aos 120 e 180 dias (p=0,001). O ventrículo esquerdo apresentou significativa redução da área de sua cavidade, 90 dias após a indução do enfisema pulmonar, acompanhada de discreto espessamento de sua parede. CONCLUSÕES: O modelo experimental empregado foi eficiente para induzir morfologicamente o enfisema pulmonar. A presença de enfisema pulmonar não provocou alterações morfológicas na parede do ventrículo direito e septo interventricular. A destruição alveolar induziu hipertrofia do ventrículo esquerdo e dilatação do ventrículo direito.