Decellularization as a method to reduce calcification in bovine pericardium bioprosthetic valves.

OBJECTIVES: Decellularization is an alternative method for processing biological tissues with decreased antigenicity and resistance to calcification. The aim of this study was to characterize the properties of decellularized (dCell) bovine pericardium fixed with 0.1% glutaraldehyde (GA) and to evaluate outcomes of bioprosthetic valves constructed with this tissue when implanted in the mitral position of juvenile sheep. METHODS: Bioprosthetic mitral valves were constructed with fresh bovine pericardium fixed in 0.5% GA (control group) or dCell bovine pericardium fixed in 0.1% GA (study group). Before implantation, samples were submitted to histological (haematoxylin-eosin, Movat and 4',6-diamidino-2-phenylindole), biochemical (residual deoxyribonucleic acid and α-gal epitopes) and biomechanical characterization. Valves were implanted (n = 8 in each group) as a mitral valve replacement for 180 days in sheep and explants were re-evaluated histologically and for calcification with radiological studies and calcium content determination. RESULTS: Unimplanted dCell pericardia exhibited a well-preserved extracellular matrix with absence of cells, a 77% reduction in deoxyribonucleic acid levels and with no detectable α-gal epitopes. When compared to controls, they had lower ultimate tensile strength (7.3 ± 5.4 vs 10.2 ± 3.0 mPa, P = 0.04) and greater percentage elongation in the longitudinal direction (29 ± 6.5% vs 23.8 ± 5.1%, P = 0.02). After 180 days in mitral position, dCell valves showed pliable leaflets without macroscopic signs of calcification. Histologically, dCell leaflets had intact collagen fibres, better tissue remodelling and a significant 89% reduction in calcium content. CONCLUSIONS: This study demonstrates that bioprosthetic valves constructed with dCell bovine pericardium fixed in low GA concentration were resistant to calcification and may thereby improve long-term durability of the tissue.

Long-Term Results of Mitral Valve Repair.

INTRODUCTION: Current guidelines state that patients with severe mitral regurgitation should be treated in reference centers with a high reparability rate, low mortality rate, and durable results. OBJECTIVE: To analyze our global experience with the treatment of organic mitral regurgitation from various etiologies operated in a single center. METHODS: We evaluated all surgically treated patients with organic mitral regurgitation from 2004-2017. Patients were evaluated clinically and by echocardiography every year. We determined early and late survival rates, valve related events and freedom from recurrent mitral regurgitation and tricuspid regurgitation. Valve failure was defined as any mitral regurgitation ≥ moderate degree or the need for reoperation for any reason. RESULTS: Out of 133 patients with organic mitral regurgitation, 125 (93.9%) were submitted to valve repair. Mean age was 57±15 years and 52 patients were males. The most common etiologies were degenerative disease (73 patients) and rheumatic disease (34 patients). Early mortality was 2.4% and late survival was 84.3% at 10 years, which are similar to the age- and gender-matched general population. Only two patients developed severe mitral regurgitation, and both were reoperated (95.6% at 10 years). Freedom from mitral valve failure was 84.5% at 10 years, with no difference between degenerative and rheumatic valves. Overall, late ≥ moderate tricuspid regurgitation was present in 34% of the patients, being more common in the rheumatic ones. The use of tricuspid annuloplasty abolished this complication. CONCLUSION: We have demonstrated that mitral regurgitation due to organic mitral valve disease from various etiologies can be surgically treated with a high repair rate, low early mortality and long-term survival that are comparable to the matched general population. Concomitant treatment of atrial fibrillation and tricuspid valve may be important adjuncts to optimize long-term results.

Fresh decellularized versus standard cryopreserved pulmonary allografts for right ventricular outflow tract reconstruction during the Ross procedure: a propensity-matched study.

OBJECTIVES: Recent studies have shown favourable early results with decellularized allografts (DAs) for right ventricular outflow tract reconstruction during the Ross procedure. However, mid- and long-term outcome data are still scarce. The objective of this study was to compare the durability of fresh DAs with standard cryopreserved allografts (SCAs) in patients undergoing the Ross procedure. METHODS: Two hundred patients underwent the Ross procedure with DA and 202 with SCA. Using propensity score matching, mid- and long-term clinical outcome and echocardiographic allograft function over time were compared. RESULTS: One hundred and thirty DA patients (median age 28 years, 71.5% men, mean follow-up 4.2 ± 2.6 years) were matched with 130 SCA patients (median age 30 years, 69.2% men, mean follow-up 13 ± 4.5 years). After matching, there were no differences in baseline characteristics. In the matched DA vs SCA groups, actuarial 8-year freedom from allograft dysfunction (DA = 86.7% vs SCA = 87.3%, P = 0.183) and freedom from allograft reintervention (DA = 99.2% vs SCA = 97.6%, P = 0.642) were comparable. Longitudinal echocardiographic analyses showed a significantly lower progression rate of peak right ventricular outflow tract gradients in the DA group during the first 3 years after the operation. Absolute gradients over time were slightly lower in DA when compared with SCA, although 95% confidence intervals overlapped. CONCLUSIONS: Up to 8 years of follow-up, DA and SCA used for right ventricular outflow tract reconstruction in the Ross procedure are associated with comparably excellent clinical and haemodynamic outcome. Longer follow-up and dedicated echocardiographic studies are still necessary to confirm the long-term performance of the DAs.

Long-term results of mitral valve repair

Abstract Introduction: Current guidelines state that patients with severe mitral regurgitation should be treated in reference centers with a high reparability rate, low mortality rate, and durable results. Objective: To analyze our global experience with the treatment of organic mitral regurgitation from various etiologies operated in a single center. Methods: We evaluated all surgically treated patients with organic mitral regurgitation from 2004-2017. Patients were evaluated clinically and by echocardiography every year. We determined early and late survival rates, valve related events and freedom from recurrent mitral regurgitation and tricuspid regurgitation. Valve failure was defined as any mitral regurgitation ≥ moderate degree or the need for reoperation for any reason. Results: Out of 133 patients with organic mitral regurgitation, 125 (93.9%) were submitted to valve repair. Mean age was 57±15 years and 52 patients were males. The most common etiologies were degenerative disease (73 patients) and rheumatic disease (34 patients). Early mortality was 2.4% and late survival was 84.3% at 10 years, which are similar to the age- and gender-matched general population. Only two patients developed severe mitral regurgitation, and both were reoperated (95.6% at 10 years). Freedom from mitral valve failure was 84.5% at 10 years, with no difference between degenerative and rheumatic valves. Overall, late ≥ moderate tricuspid regurgitation was present in 34% of the patients, being more common in the rheumatic ones. The use of tricuspid annuloplasty abolished this complication. Conclusion: We have demonstrated that mitral regurgitation due to organic mitral valve disease from various etiologies can be surgically treated with a high repair rate, low early mortality and long-term survival that are comparable to the matched general population. Concomitant treatment of atrial fibrillation and tricuspid valve may be important adjuncts to optimize long-term results.

20 years experience with the Ross operation in middle-aged patients: the autologous principle is still alive.

Objectives: Review our long-term results with the Ross operation in middle-aged patients. Methods: Between 1995 and 2016, 129 consecutive patients (106 males); mean age (47.2 ± 5.2 years) underwent a Ross operation. Right ventricular outflow tract (RVOT) reconstruction was performed with cryopreserved (n = 45) or decellularized allografts (n = 84). Mean follow-up was 8.4 ± 5.3 years (0.1 20.5 years). We analyzed early and late mortality, as well as valve related events and the need for reoperations. Results: Early mortality was 1.6% and late survival was 87.6% at 16 years. There were 4 reoperations on the pulmonary autograft (96% freedom at 16 years) and 2 on the pulmonary allografts (99% freedom at 16 years). The 16-year freedom from more than mild aortic insufficiency (AI) and a late root diameter >45 mm was 64% and 71%, respectively. Patients with the preoperative diagnosis of AI are at greater risk for these complications. Among the allografts, decellularized allografts showed superior freedom from structural valve dysfunction. Conclusions: The Ross operation in this cohort was associated with long-term survival similar to the general population and low incidence of reoperations. Patients with the preoperative diagnosis of AI are at increased risk for late autograft insufficiency and root dilatation. Decellularized allografts presented the best results for reconstruction of the RVOT. These results support the conclusion that the Ross operation has an important role in the treatment of middle-aged patients with aortic valve disease, especially those with pure aortic stenosis.

Reduced Progression of Cardiac Allograft Vasculopathy with Routine Use of Induction Therapy with Basiliximab / Redução da Progressão da Doença Vascular do Enxerto Cardíaco com o Uso Rotineiro da Terapia de Indução com Basiliximab

AbstractIntroduction:Cardiac allograft vasculopathy (CAV) is a major limitation for long-term survival of patients undergoing heart transplantation (HT). Some immunosuppressants can reduce the risk of CAV.Objectives:The primary objective was to evaluate the variation in the volumetric growth of the intimal layer measured by intracoronary ultrasound (IVUS) after 1 year in patients who received basiliximab compared with that in a control group.Methods:Thirteen patients treated at a single center between 2007 and 2009 were analyzed retrospectively. Evaluations were performed with IVUS, measuring the volume of a coronary segment within the first 30 days and 1 year after HT. Vasculopathy was characterized by the volume of the intima of the vessel.Results:Thirteen patients included (7 in the basiliximab group and 6 in the control group). On IVUS assessment, the control group was found to have greater vessel volume (120–185.43 mm3 vs. 127.77–131.32 mm3; p = 0.051). Intimal layer growth (i.e., CAV) was also higher in the control group (27.30–49.15 mm3 [∆80%] vs. 20.23–26.69 mm3[∆33%]; p = 0.015). Univariate regression analysis revealed that plaque volume and prior atherosclerosis of the donor were not related to intima growth (r = 0.15, p = 0.96), whereas positive remodeling was directly proportional to the volumetric growth of the intima (r = 0.85, p < 0.001).Conclusion:Routine induction therapy with basiliximab was associated with reduced growth of the intima of the vessel during the first year after HT.

ResumoFundamento:A doença vascular do enxerto (DVE) constitui uma grande limitação de sobrevida a longo prazo de pacientes submetidos a transplante cardíaco (TxC). Alguns imunossupressores diminuem o aparecimento da DVE.Objetivos:O principal objetivo foi avaliar, através de ultrassonografia intracoronária (USIC), a variação do crescimento volumétrico da camada íntima e comparar, após um ano, o grupo que recebeu basiliximab com um grupo de controle.Métodos:Treze pacientes de um único centro foram analisados retrospectivamente de 2007 a 2009. As análises foram feitas através de USIC, medindo-se o volume de um segmento coronariano nos primeiros 30 dias e um ano após o TxC. A vasculopatia foi caracterizada pelo volume da camada íntima do vaso.Resultados:O estudo incluiu 13 pacientes (7 no grupo com o basiliximab e 6 no grupo de controle). A análise por USIC revelou que o grupo de controle apresentou maior crescimento volumétrico do vaso (131,32 a 127,77 mm3 x 120 a 185,43 mm3 p = 0,051). O crescimento da camada íntima (CCI) também foi maior no grupo de controle [Basiliximab: 20,23 a 26,69 mm3 (∆ 33%); Controle: 27,30 a 49,15 mm3(∆ 80% p = 0,015)]. De acordo com a regressão univariada, o volume da placa aterosclerótica prévia do doador não teve relação com o crescimento da íntima (r = 0,15, p = 0,96), enquanto que o remodelamento positivo do vaso foi diretamente proporcional ao crescimento da íntima (r = 0,85, p < 0,001).Conclusão:A terapia de indução de rotina com basiliximab está associada à redução do crescimento da camada íntima do vaso no primeiro ano após o transplante cardíaco.

Reduced progression of cardiac allograft vasculopathy with routine use of induction therapy with basiliximab.

INTRODUCTION: Cardiac allograft vasculopathy (CAV) is a major limitation for long-term survival of patients undergoing heart transplantation (HT). Some immunosuppressants can reduce the risk of CAV. OBJECTIVES: The primary objective was to evaluate the variation in the volumetric growth of the intimal layer measured by intracoronary ultrasound (IVUS) after 1 year in patients who received basiliximab compared with that in a control group. METHODS: Thirteen patients treated at a single center between 2007 and 2009 were analyzed retrospectively. Evaluations were performed with IVUS, measuring the volume of a coronary segment within the first 30 days and 1 year after HT. Vasculopathy was characterized by the volume of the intima of the vessel. RESULTS: Thirteen patients included (7 in the basiliximab group and 6 in the control group). On IVUS assessment, the control group was found to have greater vessel volume (120-185.43 mm3 vs. 127.77-131.32 mm3; p = 0.051). Intimal layer growth (i.e., CAV) was also higher in the control group (27.30-49.15 mm3 [∆80%] vs. 20.23-26.69 mm3[∆33%]; p = 0.015). Univariate regression analysis revealed that plaque volume and prior atherosclerosis of the donor were not related to intima growth (r = 0.15, p = 0.96), whereas positive remodeling was directly proportional to the volumetric growth of the intima (r = 0.85, p < 0.001). CONCLUSION: Routine induction therapy with basiliximab was associated with reduced growth of the intima of the vessel during the first year after HT.

Effect of SDS-based decelullarization in the prevention of calcification in glutaraldehyde-preserved bovine pericardium: study in rats.

OBJECTIVE: The aim of study was to investigate the SDS-based decellularization process as an anticalcification method in glutaraldehyde-preserved bovine pericardium in subcutaneous rat model. METHODS: Pericardium samples with 0.5 cm² area were divide in four groups: group GDA: 0.5% glutaraldehyde-preserved pericardium (GDA); group GDA-GL: GDA + 0.2% glutamic acid (GL); group D-GDA: decellularized (D) pericardium with 0.1% SDS + GDA and group D-GDA-GL: decellularized pericardium + GDA + 0.2% glutamic acid. After this samples were implanted in 18 rats in subcutaneous position till 90 days. Each animal received samples of the four groups. The explants were performed at 45 and 90 days. The explants were subjected to histology in glass slides stained with hematoxilin-eosin and alizarin red, morphometry evaluation and the calcium content was measured by flame atomic absorption spectrometry. RESULTS: The inflammatory infiltrate was the same in all groups, however more intense in GDA and GDA-GL groups in 45 days, increasing at 90 days. The calcium contents for 45 days were: 32.52 ± 3.19 µg/mg in GDA group; 22.12 ± 3.87 µg/ mg in GDA-GL group; 1.06 ± 0.38 µg/mg in D-GDA group and 3.99 ± 5.78 µg/mg in D-GDA-GL (P< 0.001). For 90 days were 65.91 ± 24.67 µg/mg in GDA group; 38.37 ± 13.79 µg/mg in GDA-GL group; 1.24 ± 0.99 µg/mg in D-GDA group and 30.54 ± 8.21 µg/mg in D-GDA-GL (P< 0.001). Only D-GDA did not show increase rates of calcium at 45 to 90 days (P=0.314). CONCLUSION: SDS-based decellularization process reduced the inflammatory intensity and calcification in bovine pericardium in subcutaneous rat model for 90 days.

Efeito da descelularização com SDS na prevenção da calcificação em pericárdio bovino fixado em glutaraldeído: estudo em ratos / Effect of SDS-based decelullarization in the prevention of calcification in glutaraldehyde-preserved bovine pericardium: study in rats

OBJETIVO: Avaliar a descelularização com SDS como tratamento anticalcificante em pericárdio bovino fixado em glutaraldeído. MÉTODOS: Peças de 0,5 cm² foram implantadas em modelo subcutâneo de 18 ratos por até 90 dias. Foram formados quatro grupos: grupo GDA: pericárdio fixado em glutaraldeído 0,5% (GDA), grupo GDA-GL: pericárdio fixado em GDA + ácido glutâmico (GL) 0,2%, grupo D-GDA: pericárdio descelularizado (D) com SDS 0,1% e fixado em GDA e grupo D-GDA-GL: pericárdio descelularizado + GDA + ácido glutâmico 0,2%. Cada animal recebeu enxertos dos quatro grupos. Os explantes foram realizados com 45 e 90 dias. As avaliações foram: análise histológica com as colorações hematoxilina-eosina e alizarina-red, análise morfométrica e quantificação de cálcio por espectrometria de absorção atômica. RESULTADOS: O padrão de infiltrado inflamatório foi o mesmo nos quatro grupos, sendo mais intenso nos grupos GDA e GDA-GL aos 45 dias, ficando mais evidente aos 90 dias. O conteúdo de cálcio aos 45 dias foi de 32,52 ± 3,19 µg/ mg no grupo GDA; 22,12 ± 3,87 µg/mg no grupo GDA-GL; 1,06 ± 0,38 µg/mg no grupo D-GDA e 3,99 ± 5,78 µg/mg no grupo D-GDA-GL (P< 0,001). Aos 90 dias, foi de 65,91 ± 24,67 µg/mg no grupo GDA; 38,37 ± 13,79 µg/mg no grupo GDA-GL; 1,24 ± 0,99 µg/mg no grupo D-GDA e 30,54 ± 8,21 µg/mg no grupo D-GDA-GL (P< 0,001). O grupo D-GDA foi o único que não apresentou progressão da calcificação de 45 para 90 dias (P=0,314). CONCLUSÃO: A descelularização com SDS reduziu o processo inflamatório e inibiu a calcificação em pericárdio bovino implantado em modelo subcutâneo de ratos até 90 dias.

OBJECTIVE: The aim of study was to investigate the SDS-based decellularization process as an anticalcification method in glutaraldehyde-preserved bovine pericardium in subcutaneous rat model. METHODS: Pericardium samples with 0.5 cm² area were divide in four groups: group GDA: 0.5% glutaraldehydepreserved pericardium (GDA); group GDA-GL: GDA + 0.2% glutamic acid (GL); group D-GDA: decellularized (D) pericardium with 0.1% SDS + GDA and group D-GDA-GL: decellularized pericardium + GDA + 0.2% glutamic acid. After this samples were implanted in 18 rats in subcutaneous position till 90 days. Each animal received samples of the four groups. The explants were performed at 45 and 90 days. The explants were subjected to histology in glass slides stained with hematoxilin-eosin and alizarin red, morphometry evaluation and the calcium content was measured by flame atomic absorption spectrometry. RESULTS: The inflammatory infiltrate was the same in all groups, however more intense in GDA and GDA-GL groups in 45 days, increasing at 90 days. The calcium contents for 45 days were: 32.52 ± 3.19 µg/mg in GDA group; 22.12 ± 3.87 µg/ mg in GDA-GL group; 1.06 ± 0.38 µg/mg in D-GDA group and 3.99 ± 5.78 µg/mg in D-GDA-GL (P< 0.001). For 90 days were 65.91 ± 24.67 µg/mg in GDA group; 38.37 ± 13.79 µg/mg in GDA-GL group; 1.24 ± 0.99 µg/mg in D-GDA group and 30.54 ± 8.21 µg/mg in D-GDA-GL (P< 0.001). Only D-GDA did not show increase rates of calcium at 45 to 90 days (P=0.314). CONCLUSION: SDS-based decellularization process reduced the inflammatory intensity and calcification in bovine pericardium in subcutaneous rat model for 90 days.

Decellularization as an anticalcification method in stentless bovine pericardium valve prosthesis: a study in sheep.

OBJECTIVE: The objective was to analyze the decellularization process with SDS in glutaraldehyde-preserved bovine pericardium as an anticalcification method in a circulatory sheep model. METHODS: The valved tubs were implanted in pulmonary artery position in sheep by 180 days. The animals were divided in two groups of 8 animals: control group--glutaraldehyde-preserved bovine pericardium and the study group--decellularized bovine pericardium with 0,1% SDS and glutaraldehyde-preserved. After explantation the tubs were analized by x-ray macroscopy, hematoxilin-eosin, alizarin-red and Russel-Movatz pentacromic histology. The calcium content was measured by flame atomic absorption spectrometry. RESULTS: There was no early mortality, but two animals in each group died during the study. All cusps in the control group were severely calcified and in some points in the conduits, while the decellularized group did not show macroscopic calcification. Data were proved by x-ray and histologycal exams. The matrix was preserved in histologycal analysis in decellularized group, without gross calcification. The wall conduits calcium content was 35,25 ± 42,13 µg/mg in the control group versus 15,75 ± 10,44 µg/mg in the decellularized one: in the cusps was 264,4 ± 126,16 µg/mg in control group versus 94,29 ± 27,05 µg/mg in decellularized group (P = 0,009). CONCLUSION: The decellularization with 0.1% SDS was effective as an anticalcification method in bovine pericardial grafts implanted in a sheep circulatory model for 180 days.

Effects of cryopreservation and/or decellularization on extracellular matrix of porcine valves.

The objective of this study was to evaluate the morphology of decellularized and/or cryopreserved porcine pulmonary valves, to determine a solution capable of completely remove the cells without damaging the extracellular matrix. Porcine pulmonary valves were incubated for 24 hs in sodium deoxicholate 1% or sodium dodecyl sulfate 0.1 and 0.3%, with or without associated cryopreservation. Evaluation was done with optical microscopy (Hematoxilin-Eosin, Acetic Orcein and Gomori) and with morphometric analysis. The effectiveness of the solutions was variable, but the best results were obtained with the sodium dodecyl sulfate solution 0.1%.

Descelularização como método anticalcificante em próteses valvares de pericárdio bovino sem suporte: estudo em ovinos / Decellularization as an anticalcification method in stentless bovine pericardium valve prosthesis: a study in sheep

OBJETIVO: Avaliar o processo de descelularização com dodecil sulfato de sódio (SDS) como método anticalcificante em próteses de pericárdio bovino fixadas em glutaraldeído, em modelo circulatório de ovinos. MÉTODOS: Tubos valvulados de pericárdio bovino foram implantados em posição pulmonar de ovinos por 180 dias. Os animais foram divididos em dois grupos com oito animais: grupo controle, com condutos de pericárdio fixado em glutaraldeído e grupo estudo, com pericárdio descelularizado com SDS 0,1% e posteriormente fixado em GDA. Os explantes foram submetidos à análise macroscópica, histológica com hematoxilina-eosina, alizarina-red e pentacrômico de Russel-Movatz, estudo radiológico e quantificação de cálcio com espectrometria de absorção atômica. RESULTADOS: Não houve mortalidade imediata, porém dois animais de cada grupo faleceram na evolução tardia. Os enxertos do grupo controle apresentavam intensa calcificação das cúspides e em algumas regiões dos condutos, enquanto que os enxertos descelularizados apresentavam-se preservados, sem calcificações macroscópicas evidentes. Esses resultados foram comprovados por análise histológica e radiográfica. Histologicamente, os enxertos descelularizados tiveram sua matriz melhor preservada e com diminuição acentuada da calcificação. O conteúdo de cálcio nos condutos foi de 35±42 µg/mg de tecido no grupo controle versus 15 ±10 µg/mg nos descelularizados. Nas cúspides valvares, esses valores foram de 264±126 µg/mg no grupo controle versus 94±27 µg/mg nos descelularizados (P=0,009). CONCLUSÃO: A descelularização com SDS 0,1% foi efetiva como método anticalcificante em condutos de pericárdio bovino implantados em modelo circulatório de ovinos por 180 dias.

OBJECTIVE: The objective was to analyze the decellularization process with SDS in glutaraldehyde-preserved bovine pericardium as an anticalcification method in a circulatory sheep model. METHODS: The valved tubs were implanted in pulmonary artery position in sheep by 180 days. The animals were divided in two groups of 8 animals: control group glutaraldehyde-preserved bovine pericardium and the study group - decellularized bovine pericardium with 0,1% SDS and glutaraldehyde-preserved. After explantation the tubs were analized by x-ray macroscopy, hematoxilin-eosin, alizarin-red and Russel-Movatz pentacromic histology. The calcium content was measured by flame atomic absorption spectrometry. RESULTS: There was no early mortality, but two animals in each group died during the study. All cusps in the control group were severely calcified and in some points in the conduits, while the decellularized group did not show macroscopic calcification. Data were proved by x-ray and histologycal exams. The matrix was preserved in histologycal analysis in decellularized group, without gross calcification. The wall conduits calcium content was 35,25±42,13 µg/mg in the control group versus 15,75±10,44 µg/mg in the decellularized one: in the cusps was 264,4±126,16 µg/mg in control group versus 94,29±27,05 µg/mg in decellularized group (P=0,009). CONCLUSION: The decellularization with 0.1% SDS was effective as an anticalcification method in bovine pericardial grafts implanted in a sheep circulatory model for 180 days.

Efeito da criopreservação e/ou da descelularização na matriz extracelular de condutos valvados porcinos / Effects of cryopreservation and/or decellularization on extracellular matrix of porcine valves

O objetivo desse estudo foi avaliar a morfologia de valvas pulmonares porcinas criopreservadas e/ou descelularizadas para determinar uma solução que remova as células, sem promover danos à matriz extracelular. Valvas pulmonares porcinas foram incubadas por 24h em soluções de deoxicolato de sódio 1% e de dodecil sulfato de sódio 0,1% e 0,3%, com ou sem criopreservação adicional. A avaliação foi feita com microscopia óptica (hematoxilina eosina, orceína acética ou Gomori) e por morfometria. A efetividade das soluções foi variável, mas os melhores resultados foram obtidos com enxertos frescos descelularizados com dodecil sulfato de sódio 0,1%.

The objective of this study was to evaluate the morphology of decelluarized and/or cryopreserved porcine pulmonary valves, to determine a solution capable of completely remove the cells without damaging the extracellular matrix. Porcine pulmonary valves were incubated for 24 hs in sodium deoxicholate 1% or sodium dodecyl sulfate 0.1 and 0.3%, with or without associated cryopreservation. Evaluation was done with optical microscopy (Hematoxilin-Eosin, Acetic Orcein and Gomori) and with morphometric analysis. The effectiviness of the solutions was variable, but the best results were obtained with the sodium dodecyl sulfate solution 0.1%.

Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model.

INTRODUCTION: The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration. OBJECTIVE: The objective of this experimental and descriptive study is to evaluate the biological and functional behavior of decellularized pulmonary homografts (Decell-H), treated by a sodium dodecil sulfate solution (0.1%), developed in our University (Pontifícia Universidade Católica do Paraná). For the characterization of Decell-H performance, parameters like recellularization, calcification, and echocardiographic data will be analyzed. METHODS: Eight juvenile sheep were submitted to the implantation of the Decell-H sutured into orthotopic position, through a left thoracotomy and with cardiopulmonary bypass support. They were followed-up clinically and by periodical echocardiograms until the explantation, which were performed in different time for every two sheep: seven, 30, 90 and 180 postoperative days. For histological analysis we used Hematoxilin-eosin, Movat and Alizarin-Red staining. RESULTS: The sheep reached their follow-up period in a good clinical state. There was no valve regurgitation or stenonis by the echocardiogram. The animals submitted to the explantation in 90 and 180 days had a significant somatic growth and these Decell-H(s) had a diameter increase, without central valve insufficiency. Histologically, all homografts preserved their extra-cellular matrix organization and were progressively recellularized, without calcification. CONCLUSION: In this experimental model, the Decell-H behaved as an excellent valve substitute.

Avaliação do comportamento biológico de homoenxertos valvares pulmonares descelularizados: estudo experimental em ovinos / Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model

INTRODUÇÃO: Não havendo um substituto valvar ideal, os homoenxertos criopreservados são considerados uma boa opção, pelo excelente perfil hemodinâmico, baixa incidência de tromboembolismo, resistência a infecções e durabilidade a médio prazo. Porém, estão sujeitos à progressiva degeneração, especialmente em crianças e adultos jovens. Sua antigenicidade desencadeia uma resposta imunológica que contribui para sua degeneração, calcificação e falência. Para diminuir esta antigenicidade, desenvolveu-se o processo de descelularização. Pela ação de detergentes e enzimas, este processo remove os componentes celulares do homoenxerto, diminuindo sua imunogenicidade e, provavelmente, retardando sua degeneração. OBJETIVO: O objetivo deste estudo, experimental e descritivo, é analisar o comportamento histológico e funcional de homoenxertos pulmonares ovinos descelularizados (H-descel) por uma nova solução, composta principalmente de dodecil sulfato de sódio a 0,1 por cento e desenvolvida na PUCPR. Para caracterizar este comportamento, serão avaliados o repovoamento celular, a ocorrência de calcificação e a função valvar ao ecocardiograma. MÉTODOS: A amostra foi constituída de oito ovinos, submetidos ao implante de H-descel em posição ortotópica, através de uma toracotomia esquerda, com auxílio de circulação extracorpórea. Os animais foram acompanhados clinicamente e por ecocardiogramas periódicos até o explante, realizados em prazos predefinidos para cada dois animais: sete, 30, 90 e 180 dias. A análise histológica foi realizada por colorações Hematoxilina-eosina, Pentacrômio de Movat e Alizarina Red. RESULTADOS: Todos os animais sobreviveram ao procedimento e atingiram seus períodos de seguimento. Não houve insuficiência ou estenose destes enxertos ao ecocardiograma. Os animais submetidos aos explantes em 90 e 180 dias tiveram significativos ganhos ponderais e estes H-descel aumentaram de diâmetro, sem desenvolver insuficiência. À histologia, todos mantiveram a organização de sua matriz extracelular, foram progressivamente repovoados e não apresentaram calcificação. CONCLUSÃO: Neste modelo experimental, os H-descel mostraram-se excelentes substitutos valvares a médio prazo.

INTRODUCTION: The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration. OBJECTIVE: The objective of this experimental and descriptive study is to evaluate the biological and functional behavior of decellularized pulmonary homografts (Decell-H), treated by a sodium dodecil sulfate solution (0.1 percent), developed in our University (Pontifícia Universidade Católica do Paraná). For the characterization of Decell-H performance, parameters like recellularization, calcification, and echocardiographic data will be analyzed. METHODS: Eight juvenile sheep were submitted to the implantation of the Decell-H sutured into orthotopic position, through a left thoracotomy and with cardiopulmonary bypass support. They were followed-up clinically and by periodical echocardiograms until the explantation, which were performed in different time for every two sheep: seven, 30, 90 and 180 postoperative days. For histological analysis we used Hematoxilin-eosin, Movat and Alizarin-Red staining. RESULTS: The sheep reached their follow-up period in a good clinical state. There was no valve regurgitation or stenonis by the echocardiogram. The animals submitted to the explantation in 90 and 180 days had a significant somatic growth and these Decell-H(s) had a diameter increase, without central valve insufficiency. Histologically, all homografts preserved their extra-cellular matrix organization and were progressively recellularized, without calcification. CONCLUSION: In this experimental model, the Decell-H behaved as an excellent valve substitute.

Decellularized heterografts versus cryopreserved homografts: experimental study in sheep model.

OBJECTIVES: The aim of this study is to assess the biological behaviour of porcine decellularized heterografts (Desc group) compared with cryopreserved homografts (Crio group) implanted in juvenile sheep. METHODS: Decellularized porcine pulmonary heterografts were implanted in five animals and cryopreserved pulmonary homografts in another five. The animals were followed-up for a mean of 280 +/- 14 days. The valve diameter was measured by echocardiography, which was performed at the 30th postoperative day, and before the explantation. The valves were also assessed macroscopically. Histological evaluation was performed using H.E., Gomori and Weigert staining. Immunohistochemistry specified different cell types (Factor VIII, CD3, Vimentin and CD68). Calcium quantity was analyzed using atomic absortion spectometry. RESULTS: There was one death in the Desc group due to endocarditis. The valves of Crio group showed decrease in the cellularity whereas the valves of Desc group showed matrix repopulation with endothelial and interstitial cells. Loss of collagen density and disarrangement of the normal fiber architecture was observed in Crio group. Calcium content demonstrated higher levels on the cusps and conduits in Crio group comparatively with Desc group. (P=0.016). The mean valvular diameter at the explantation was significantly increased (P=0.025) in the Desc group. CONCLUSIONS: Decellularized heterografts had a different biological behaviour when compared to cryopreserved homografts and become repopulated by cells with fibroblasts and endothelial cells characteristics. The matrix was preserved and some regenerative potential was present.