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Ronaldo Nogueira De Moraes Pitombo - One of the best experts on this subject based on the ideXlab platform.
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Effect of freeze-drying on the mechanical, physical and morphological properties of glutaraldehyde-treated Bovine Pericardium: evaluation of freeze-dried treated Bovine Pericardium properties
Journal of applied biomaterials & biomechanics : JABB, 2010Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Marina J.s. Maizato, Bronislaw Polakiewicz, Marisa M. Beppu, Olga Z. Higa, Ronaldo Nogueira De Moraes PitomboAbstract:PurposeBiomaterials have been widely used in the field of regenerative medicine. Bovine Pericardium tissue has been successfully used as a bioprosthetic material in manufacturing heart valves, but studies concerning the tissue are ongoing in order to improve its storage, preservation and transportation. This article provides an overview of the characteristics of Bovine Pericardium tissue chemically treated after the freeze-drying process. These characteristics are essential to evaluate the changes or damage to the tissue during the process.MethodsThe mechanical properties of the tissue were analyzed by three different methods due to its anisotropic characteristics. The physical properties were analyzed by a colorimetric method, while the morphological properties were evaluated by scanning electron microscopy (SEM).ResultsThe freeze-dried Bovine Pericardium showed no significant change in its mechanical properties. There was no significant change in the elasticity of the tissue (p>0.05) and no color change...
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Bovine Pericardium coated with biopolymeric films as an alternative to prevent calcification: In vitro calcification and cytotoxicity results
Materials Science and Engineering: C, 2010Co-Authors: Grínia M. Nogueira, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Andrea C.d. Rodas, Raquel Farias Weska, Cassiano Gomes Aimoli, Adolfo Alberto Leiner, Marisa Masumi BeppuAbstract:Abstract Bovine Pericardium, for cardiac valve fabrication, was coated with either chitosan or silk fibroin film. In vitro calcification tests of coated and non coated Bovine Pericardium were performed in simulated body fluid solution in order to investigate potential alternatives to minimize calcification on implanted heart valves. Complementary, morphology was assessed by scanning electron microscopy — SEM; X-ray diffraction (XRD) and infrared spectroscopy (FTIR-ATR) were performed for structural characterization of coatings and biocompatibility of chitosan. Silk fibroin films were assayed by in vitro cytotoxicity and endothelial cell growth tests. Bovine Pericardium coated with silk fibroin or chitosan did not present calcification during in vitro calcification tests, indicating that these biopolymeric coatings do not induce Bovine Pericardium calcification. Chitosan and silk fibroin films were characterized as non cytotoxic and silk fibroin films presented high affinity to endothelial cells. The results indicate that Bovine Pericardium coated with silk fibroin is a potential candidate for cardiac valve fabrication, since the affinity of silk fibroin to endothelial cells can be explored to induce the tissue endothelization and therefore, increase valve durability by increasing their mechanical resistance and protecting them against calcification.
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the influence of freezing rates on Bovine Pericardium tissue freeze drying
Brazilian Archives of Biology and Technology, 2009Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Virgilio Tattini, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Ana Maria Irene Bartolomeu Ayrosa, Marisa Masumi Beppu, Ronaldo Nogueira De Moraes PitomboAbstract:The Bovine Pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a Bovine Pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the Bovine Pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.
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Prospects in lyophilization of Bovine Pericardium.
Artificial Organs, 2009Co-Authors: Adolfo A. Leirner, Virgilio Tattini, Ronaldo Nogueira De Moraes PitomboAbstract:Almost 30 years after the introduction of heart valve prostheses patients worldwide are benefiting from the implant of these devices. Among the various types of heart valves, the ones made of treated Bovine Pericardium have become a frequently used replacement of the heart's native valve. Lyophilization, also known as freeze-drying, is an extremely useful technique for tissue storage for surgical applications. This article gives a brief overview on the current Bovine Pericardium lyophilization development, including the chemical modification to improve physical-chemical characteristics and the advanced technologies used to guarantee a high-quality product. It was shown that lyophilization process can be successfully applied as a method of Bovine Pericardium preservation and also as a technological tool to prepare new materials obtained by chemical modification of native tissues.
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Histological evaluation of biocompatibility of lyophilized Bovine Pericardium implanted subcutaneously in rats.
Artificial organs, 2008Co-Authors: Marina J.s. Maizato, Ronaldo Nogueira De Moraes Pitombo, Olga Z. Higa, Mara D. Pires, Mauro Canzian, Adolfo A. LeirnerAbstract:: This article aims at investigating in vivo evaluation of lyophilization procedure on the biocompatibility of Bovine Pericardium treated with glutaraldehyde (GA). The Bovine Pericardium was fixed with 0.5% glutaraldehyde during 10 days and preserved in 4% formaldehyde (FA). Two groups of samples were prepared from treated membranes: Group 1, nonlyophilized samples and Group 2, lyophilized samples. Male Sprague-Dawley rats (4 weeks after birth) were anesthetized (pentobarbital sodium 25 mg/kg of body weight) and in each one were implanted subcutaneously in the dorsal region a sample from Group 1 and another from Group 2. These samples were explanted after 30 days for histological analysis. No intercurrences took place after the surgery. No differences (P > 0.05) in the calcification, granulomatous reaction, mononuclear infiltration, and granulation tissue development was observed between both groups. The implanted lyophilized samples presented a trend for a reduced inflammatory reaction. Lyophilization of the Bovine Pericardium does not seem to increase the above listed tissue reaction.
Adolfo A. Leirner - One of the best experts on this subject based on the ideXlab platform.
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Effect of freeze-drying on the mechanical, physical and morphological properties of glutaraldehyde-treated Bovine Pericardium: evaluation of freeze-dried treated Bovine Pericardium properties
Journal of applied biomaterials & biomechanics : JABB, 2010Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Marina J.s. Maizato, Bronislaw Polakiewicz, Marisa M. Beppu, Olga Z. Higa, Ronaldo Nogueira De Moraes PitomboAbstract:PurposeBiomaterials have been widely used in the field of regenerative medicine. Bovine Pericardium tissue has been successfully used as a bioprosthetic material in manufacturing heart valves, but studies concerning the tissue are ongoing in order to improve its storage, preservation and transportation. This article provides an overview of the characteristics of Bovine Pericardium tissue chemically treated after the freeze-drying process. These characteristics are essential to evaluate the changes or damage to the tissue during the process.MethodsThe mechanical properties of the tissue were analyzed by three different methods due to its anisotropic characteristics. The physical properties were analyzed by a colorimetric method, while the morphological properties were evaluated by scanning electron microscopy (SEM).ResultsThe freeze-dried Bovine Pericardium showed no significant change in its mechanical properties. There was no significant change in the elasticity of the tissue (p>0.05) and no color change...
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the influence of freezing rates on Bovine Pericardium tissue freeze drying
Brazilian Archives of Biology and Technology, 2009Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Virgilio Tattini, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Ana Maria Irene Bartolomeu Ayrosa, Marisa Masumi Beppu, Ronaldo Nogueira De Moraes PitomboAbstract:The Bovine Pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a Bovine Pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the Bovine Pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.
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Prospects in lyophilization of Bovine Pericardium.
Artificial Organs, 2009Co-Authors: Adolfo A. Leirner, Virgilio Tattini, Ronaldo Nogueira De Moraes PitomboAbstract:Almost 30 years after the introduction of heart valve prostheses patients worldwide are benefiting from the implant of these devices. Among the various types of heart valves, the ones made of treated Bovine Pericardium have become a frequently used replacement of the heart's native valve. Lyophilization, also known as freeze-drying, is an extremely useful technique for tissue storage for surgical applications. This article gives a brief overview on the current Bovine Pericardium lyophilization development, including the chemical modification to improve physical-chemical characteristics and the advanced technologies used to guarantee a high-quality product. It was shown that lyophilization process can be successfully applied as a method of Bovine Pericardium preservation and also as a technological tool to prepare new materials obtained by chemical modification of native tissues.
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Histological evaluation of biocompatibility of lyophilized Bovine Pericardium implanted subcutaneously in rats.
Artificial organs, 2008Co-Authors: Marina J.s. Maizato, Ronaldo Nogueira De Moraes Pitombo, Olga Z. Higa, Mara D. Pires, Mauro Canzian, Adolfo A. LeirnerAbstract:: This article aims at investigating in vivo evaluation of lyophilization procedure on the biocompatibility of Bovine Pericardium treated with glutaraldehyde (GA). The Bovine Pericardium was fixed with 0.5% glutaraldehyde during 10 days and preserved in 4% formaldehyde (FA). Two groups of samples were prepared from treated membranes: Group 1, nonlyophilized samples and Group 2, lyophilized samples. Male Sprague-Dawley rats (4 weeks after birth) were anesthetized (pentobarbital sodium 25 mg/kg of body weight) and in each one were implanted subcutaneously in the dorsal region a sample from Group 1 and another from Group 2. These samples were explanted after 30 days for histological analysis. No intercurrences took place after the surgery. No differences (P > 0.05) in the calcification, granulomatous reaction, mononuclear infiltration, and granulation tissue development was observed between both groups. The implanted lyophilized samples presented a trend for a reduced inflammatory reaction. Lyophilization of the Bovine Pericardium does not seem to increase the above listed tissue reaction.
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lyophilized Bovine Pericardium treated with a phenethylamine diepoxide as an alternative to preventing calcification of cardiovascular bioprosthesis preliminary calcification results
Artificial Organs, 2007Co-Authors: Cassiano Gomes Aimoli, Adolfo A. Leirner, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Grínia M. Nogueira, Leandro Nascimento, Andre Baceti, Marisa Masumi BeppuAbstract:: This study investigated the calcification process that occurred on chemically treated Bovine Pericardium substrata through tests with simulated body fluid solutions. The use of Bovine Pericardium bioprosthetic valves in heart valve surgery has a significant drawback due to the calcification processes. Thus, many routes such as chemical treatments in the substratum or the adoption of systemic therapies are considered in the literature with the intention to inhibit or to decelerate this process. The presented treatment using the two different phenetylamine-diepoxide solutions showed no effects on calcification experiments as showed by the tests. However, the lyophilized Bovine Pericardium samples, treated with both solutions, did not show any detectable phosphate deposits. The lyophilization of Bovine Pericardium before chemical treatments with cross-link agents as epoxy compounds may be an alternative to the conventional calcification prevention methods, but further investigations are recommended to check if the same behavior is found in all lyophilized systems.
Marina J.s. Maizato - One of the best experts on this subject based on the ideXlab platform.
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Effect of freeze-drying on the mechanical, physical and morphological properties of glutaraldehyde-treated Bovine Pericardium: evaluation of freeze-dried treated Bovine Pericardium properties
Journal of applied biomaterials & biomechanics : JABB, 2010Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Marina J.s. Maizato, Bronislaw Polakiewicz, Marisa M. Beppu, Olga Z. Higa, Ronaldo Nogueira De Moraes PitomboAbstract:PurposeBiomaterials have been widely used in the field of regenerative medicine. Bovine Pericardium tissue has been successfully used as a bioprosthetic material in manufacturing heart valves, but studies concerning the tissue are ongoing in order to improve its storage, preservation and transportation. This article provides an overview of the characteristics of Bovine Pericardium tissue chemically treated after the freeze-drying process. These characteristics are essential to evaluate the changes or damage to the tissue during the process.MethodsThe mechanical properties of the tissue were analyzed by three different methods due to its anisotropic characteristics. The physical properties were analyzed by a colorimetric method, while the morphological properties were evaluated by scanning electron microscopy (SEM).ResultsThe freeze-dried Bovine Pericardium showed no significant change in its mechanical properties. There was no significant change in the elasticity of the tissue (p>0.05) and no color change...
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Bovine Pericardium coated with biopolymeric films as an alternative to prevent calcification: In vitro calcification and cytotoxicity results
Materials Science and Engineering: C, 2010Co-Authors: Grínia M. Nogueira, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Andrea C.d. Rodas, Raquel Farias Weska, Cassiano Gomes Aimoli, Adolfo Alberto Leiner, Marisa Masumi BeppuAbstract:Abstract Bovine Pericardium, for cardiac valve fabrication, was coated with either chitosan or silk fibroin film. In vitro calcification tests of coated and non coated Bovine Pericardium were performed in simulated body fluid solution in order to investigate potential alternatives to minimize calcification on implanted heart valves. Complementary, morphology was assessed by scanning electron microscopy — SEM; X-ray diffraction (XRD) and infrared spectroscopy (FTIR-ATR) were performed for structural characterization of coatings and biocompatibility of chitosan. Silk fibroin films were assayed by in vitro cytotoxicity and endothelial cell growth tests. Bovine Pericardium coated with silk fibroin or chitosan did not present calcification during in vitro calcification tests, indicating that these biopolymeric coatings do not induce Bovine Pericardium calcification. Chitosan and silk fibroin films were characterized as non cytotoxic and silk fibroin films presented high affinity to endothelial cells. The results indicate that Bovine Pericardium coated with silk fibroin is a potential candidate for cardiac valve fabrication, since the affinity of silk fibroin to endothelial cells can be explored to induce the tissue endothelization and therefore, increase valve durability by increasing their mechanical resistance and protecting them against calcification.
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the influence of freezing rates on Bovine Pericardium tissue freeze drying
Brazilian Archives of Biology and Technology, 2009Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Virgilio Tattini, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Ana Maria Irene Bartolomeu Ayrosa, Marisa Masumi Beppu, Ronaldo Nogueira De Moraes PitomboAbstract:The Bovine Pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a Bovine Pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the Bovine Pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.
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Histological evaluation of biocompatibility of lyophilized Bovine Pericardium implanted subcutaneously in rats.
Artificial organs, 2008Co-Authors: Marina J.s. Maizato, Ronaldo Nogueira De Moraes Pitombo, Olga Z. Higa, Mara D. Pires, Mauro Canzian, Adolfo A. LeirnerAbstract:: This article aims at investigating in vivo evaluation of lyophilization procedure on the biocompatibility of Bovine Pericardium treated with glutaraldehyde (GA). The Bovine Pericardium was fixed with 0.5% glutaraldehyde during 10 days and preserved in 4% formaldehyde (FA). Two groups of samples were prepared from treated membranes: Group 1, nonlyophilized samples and Group 2, lyophilized samples. Male Sprague-Dawley rats (4 weeks after birth) were anesthetized (pentobarbital sodium 25 mg/kg of body weight) and in each one were implanted subcutaneously in the dorsal region a sample from Group 1 and another from Group 2. These samples were explanted after 30 days for histological analysis. No intercurrences took place after the surgery. No differences (P > 0.05) in the calcification, granulomatous reaction, mononuclear infiltration, and granulation tissue development was observed between both groups. The implanted lyophilized samples presented a trend for a reduced inflammatory reaction. Lyophilization of the Bovine Pericardium does not seem to increase the above listed tissue reaction.
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lyophilized Bovine Pericardium treated with a phenethylamine diepoxide as an alternative to preventing calcification of cardiovascular bioprosthesis preliminary calcification results
Artificial Organs, 2007Co-Authors: Cassiano Gomes Aimoli, Adolfo A. Leirner, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Grínia M. Nogueira, Leandro Nascimento, Andre Baceti, Marisa Masumi BeppuAbstract:: This study investigated the calcification process that occurred on chemically treated Bovine Pericardium substrata through tests with simulated body fluid solutions. The use of Bovine Pericardium bioprosthetic valves in heart valve surgery has a significant drawback due to the calcification processes. Thus, many routes such as chemical treatments in the substratum or the adoption of systemic therapies are considered in the literature with the intention to inhibit or to decelerate this process. The presented treatment using the two different phenetylamine-diepoxide solutions showed no effects on calcification experiments as showed by the tests. However, the lyophilized Bovine Pericardium samples, treated with both solutions, did not show any detectable phosphate deposits. The lyophilization of Bovine Pericardium before chemical treatments with cross-link agents as epoxy compounds may be an alternative to the conventional calcification prevention methods, but further investigations are recommended to check if the same behavior is found in all lyophilized systems.
Darren H Freed - One of the best experts on this subject based on the ideXlab platform.
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resveratrol significantly attenuates cell mediated immune rejection against xenogenic Bovine Pericardium
Journal of Heart and Lung Transplantation, 2020Co-Authors: Jimmy J H Kang, Sabin J Bozso, Dana Boe, Jayan Nagendran, Michael C Moon, Darren H FreedAbstract:Purpose Resveratrol is a bioactive phenol shown to reduce T cell activation through inhibition of mTOR pathways. Recent studies show cell-mediated immune reactions cause structural valve deterioration (SVD) in xenograft valves. Thus, tissue-engineered heart valves (TEHV) with decellularized Bovine Pericardium have been developed to reduce the immune response. Our study examines whether resveratrol could further decrease the immune rejection against xenogenic Bovine Pericardium. Methods Human peripheral blood mononuclear cells (PBMC) were isolated and resuspended in RPMI 1640 complete medium containing 10% human serum. The cells were further split into resveratrol (50μM/ml) and a vehicle group containing ethanol (50μM/ml) and cultured overnight in a 37C incubator. 2ml of the complete medium from each group containing 1 × 10^6 PBMC cells were then aliquoted into a cell culturing plate with each well containing either native Bovine Pericardium, decellularized Bovine Pericardium, allograft Pericardium, autograft Pericardium, or no Pericardium. The exposed culture media were then collected for ELISA analysis after 1 and 3 days. Results Tumor necrosis factor-a (TNF-a), chiefly produced by macrophages in cell-mediated immunity, was measured. Resveratrol-treated cells showed a significant reduction in all of the tissue exposure types in comparison to vehicle-treated controls at both 1 and 3 days (n=4, P Conclusion Resveratrol significantly decreases cell-mediated immune rejection against xenogenic Bovine Pericardium exposures. Therefore, resveratrol may serve as adjuvant therapy in TEHV replacements to further decrease the xenogenic immune reaction shown to cause SVD.
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Resveratrol Significantly Attenuates Cell Mediated Immune Rejection against Xenogenic Bovine Pericardium.
Journal of Heart and Lung Transplantation, 2020Co-Authors: Jimmy J H Kang, Sabin J Bozso, Dana Boe, Jayan Nagendran, Michael C Moon, Darren H FreedAbstract:PURPOSE Resveratrol is a bioactive phenol shown to reduce T cell activation through inhibition of mTOR pathways. Recent studies show cell-mediated immune reactions cause structural valve deterioration (SVD) in xenograft valves. Thus, tissue-engineered heart valves (TEHV) with decellularized Bovine Pericardium have been developed to reduce the immune response. Our study examines whether resveratrol could further decrease the immune rejection against xenogenic Bovine Pericardium. METHODS Human peripheral blood mononuclear cells (PBMC) were isolated and resuspended in RPMI 1640 complete medium containing 10% human serum. The cells were further split into resveratrol (50μM/ml) and a vehicle group containing ethanol (50μM/ml) and cultured overnight in a 37C incubator. 2ml of the complete medium from each group containing 1 × 10^6 PBMC cells were then aliquoted into a cell culturing plate with each well containing either native Bovine Pericardium, decellularized Bovine Pericardium, allograft Pericardium, autograft Pericardium, or no Pericardium. The exposed culture media were then collected for ELISA analysis after 1 and 3 days. RESULTS Tumor necrosis factor-a (TNF-a), chiefly produced by macrophages in cell-mediated immunity, was measured. Resveratrol-treated cells showed a significant reduction in all of the tissue exposure types in comparison to vehicle-treated controls at both 1 and 3 days (n=4, P
Olga Z. Higa - One of the best experts on this subject based on the ideXlab platform.
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Effect of freeze-drying on the mechanical, physical and morphological properties of glutaraldehyde-treated Bovine Pericardium: evaluation of freeze-dried treated Bovine Pericardium properties
Journal of applied biomaterials & biomechanics : JABB, 2010Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Marina J.s. Maizato, Bronislaw Polakiewicz, Marisa M. Beppu, Olga Z. Higa, Ronaldo Nogueira De Moraes PitomboAbstract:PurposeBiomaterials have been widely used in the field of regenerative medicine. Bovine Pericardium tissue has been successfully used as a bioprosthetic material in manufacturing heart valves, but studies concerning the tissue are ongoing in order to improve its storage, preservation and transportation. This article provides an overview of the characteristics of Bovine Pericardium tissue chemically treated after the freeze-drying process. These characteristics are essential to evaluate the changes or damage to the tissue during the process.MethodsThe mechanical properties of the tissue were analyzed by three different methods due to its anisotropic characteristics. The physical properties were analyzed by a colorimetric method, while the morphological properties were evaluated by scanning electron microscopy (SEM).ResultsThe freeze-dried Bovine Pericardium showed no significant change in its mechanical properties. There was no significant change in the elasticity of the tissue (p>0.05) and no color change...
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Bovine Pericardium coated with biopolymeric films as an alternative to prevent calcification: In vitro calcification and cytotoxicity results
Materials Science and Engineering: C, 2010Co-Authors: Grínia M. Nogueira, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Andrea C.d. Rodas, Raquel Farias Weska, Cassiano Gomes Aimoli, Adolfo Alberto Leiner, Marisa Masumi BeppuAbstract:Abstract Bovine Pericardium, for cardiac valve fabrication, was coated with either chitosan or silk fibroin film. In vitro calcification tests of coated and non coated Bovine Pericardium were performed in simulated body fluid solution in order to investigate potential alternatives to minimize calcification on implanted heart valves. Complementary, morphology was assessed by scanning electron microscopy — SEM; X-ray diffraction (XRD) and infrared spectroscopy (FTIR-ATR) were performed for structural characterization of coatings and biocompatibility of chitosan. Silk fibroin films were assayed by in vitro cytotoxicity and endothelial cell growth tests. Bovine Pericardium coated with silk fibroin or chitosan did not present calcification during in vitro calcification tests, indicating that these biopolymeric coatings do not induce Bovine Pericardium calcification. Chitosan and silk fibroin films were characterized as non cytotoxic and silk fibroin films presented high affinity to endothelial cells. The results indicate that Bovine Pericardium coated with silk fibroin is a potential candidate for cardiac valve fabrication, since the affinity of silk fibroin to endothelial cells can be explored to induce the tissue endothelization and therefore, increase valve durability by increasing their mechanical resistance and protecting them against calcification.
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the influence of freezing rates on Bovine Pericardium tissue freeze drying
Brazilian Archives of Biology and Technology, 2009Co-Authors: Camila Figueiredo Borgognoni, Adolfo A. Leirner, Virgilio Tattini, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Ana Maria Irene Bartolomeu Ayrosa, Marisa Masumi Beppu, Ronaldo Nogueira De Moraes PitomboAbstract:The Bovine Pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a Bovine Pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the Bovine Pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.
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Histological evaluation of biocompatibility of lyophilized Bovine Pericardium implanted subcutaneously in rats.
Artificial organs, 2008Co-Authors: Marina J.s. Maizato, Ronaldo Nogueira De Moraes Pitombo, Olga Z. Higa, Mara D. Pires, Mauro Canzian, Adolfo A. LeirnerAbstract:: This article aims at investigating in vivo evaluation of lyophilization procedure on the biocompatibility of Bovine Pericardium treated with glutaraldehyde (GA). The Bovine Pericardium was fixed with 0.5% glutaraldehyde during 10 days and preserved in 4% formaldehyde (FA). Two groups of samples were prepared from treated membranes: Group 1, nonlyophilized samples and Group 2, lyophilized samples. Male Sprague-Dawley rats (4 weeks after birth) were anesthetized (pentobarbital sodium 25 mg/kg of body weight) and in each one were implanted subcutaneously in the dorsal region a sample from Group 1 and another from Group 2. These samples were explanted after 30 days for histological analysis. No intercurrences took place after the surgery. No differences (P > 0.05) in the calcification, granulomatous reaction, mononuclear infiltration, and granulation tissue development was observed between both groups. The implanted lyophilized samples presented a trend for a reduced inflammatory reaction. Lyophilization of the Bovine Pericardium does not seem to increase the above listed tissue reaction.
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lyophilized Bovine Pericardium treated with a phenethylamine diepoxide as an alternative to preventing calcification of cardiovascular bioprosthesis preliminary calcification results
Artificial Organs, 2007Co-Authors: Cassiano Gomes Aimoli, Adolfo A. Leirner, Ronaldo Nogueira De Moraes Pitombo, Marina J.s. Maizato, Bronislaw Polakiewicz, Olga Z. Higa, Grínia M. Nogueira, Leandro Nascimento, Andre Baceti, Marisa Masumi BeppuAbstract:: This study investigated the calcification process that occurred on chemically treated Bovine Pericardium substrata through tests with simulated body fluid solutions. The use of Bovine Pericardium bioprosthetic valves in heart valve surgery has a significant drawback due to the calcification processes. Thus, many routes such as chemical treatments in the substratum or the adoption of systemic therapies are considered in the literature with the intention to inhibit or to decelerate this process. The presented treatment using the two different phenetylamine-diepoxide solutions showed no effects on calcification experiments as showed by the tests. However, the lyophilized Bovine Pericardium samples, treated with both solutions, did not show any detectable phosphate deposits. The lyophilization of Bovine Pericardium before chemical treatments with cross-link agents as epoxy compounds may be an alternative to the conventional calcification prevention methods, but further investigations are recommended to check if the same behavior is found in all lyophilized systems.