Resumen
Introdução: As cúspides porcinas tratadas com glutaraldeído (GDA) são um dos tecidos biológicos mais utilizados em biopróteses, porém a calcificação tardia pós-implante constitui a causa predominante de sua falência. Objetivo: Analisar comparativamente dois métodos de prevenção da calcificação (etanol 80% e ácido L-glutâmico 0.8%) em cúspide e parede aórtica porcina implantadas no subcutâneo em ratos, tendo como grupo controle as cúspides e os segmentos de parede aórtica fixadas em glutaraldeído (GDA), num período de 15, 30 e 60 dias após implante. Métodos: Foram utilizados 45 ratos jovens, distribuídos em 3 grupos contendo 15 animais cada, que por sua vez foram subdivididos em 3 subgrupos de 5 animais, nos quais foram implantados, em 2 bolsas no subcutâneo, uma cúspide e um segmento de parede aórtica em cada. Em cada grupo assim nominados: GDA (grupo controle), E80% (grupo cuja as estruturas foram pré-tratadas com etanol 80%) e o AG 0.8% (grupo cuja as estruturas foram pré-tratadas com ácido L-glutâmico 0.8%) foram realizadas a mensuração do cálcio e análise microscópica quanto à presença de calcificação: localização e intensidade da mesma; Infiltrado inflamatório: localização e tipo, no período de 15, 30 e 60 dias após implante. Resultados: Na mensuração do cálcio na cúspide aórtica encontrou-se no grupo E80% 15 dias (1.30 ± 0.21 μg cálcio/mg tecido), E80% 30 dias (1.05 ± 0.22 μg cálcio/mg tecido) e E80% 60 dias (0.53 ± 0.42 μg cálcio/mg tecido); no grupo AG 0.8% 15 dias (12.17 ± 0.66 μg cálcio/mg tecido), AG 0.8% 30 dias (15.31 ± 2.82 μg cálcio/mg tecido) e AG 0.8% 60 dias (34.24 ± 16.28 μg cálcio/mg tecido) com o grupo controle GDA 15 dias (12.44 ± 2.26 μg cálcio/mg tecido), GDA 30 dias (13.44 ± 3.34 μg cálcio/mg tecido) e GDA 60 dias (50.85 ± 8.71 μg cálcio/mg tecido). Em relação à mensuração do cálcio na parede aórtica, encontrou-se no grupo de E80% 15 dias (4.62 ± 0.68 μg cálcio/ mg tecido), E80% 30 dias (9.47 ± 2.59 μg cálcio/mg tecido) e E80% 60 dias (23.56 ± 7.75 μg cálcio/mg tecido) no grupo de AG 0.8% 15 dias (4.31 ± 0.85 μg cálcio/mg tecido), AG 0.8% 30 dias (7.69 ± 1.48 μg cálcio/mg tecido) e AG 0.8% 60 dias (20.50 ± 1.22 μg cálcio/mg tecido) com o grupo controle GDA 15 dias (7.34 ± 1.32 μg cálcio/mg tecido), GDA 30 dias (9.28 ± 0.76 μg cálcio/mg tecido) e GDA 60 dias (27.60 ± 1.08 μg cálcio/mg tecido). Na avaliação microscópica da cúspide aórtica houve uma progressiva calcificação naquelas submetidas a fixação com GDA. Esse processo foi parcialmente encontrado com o AG 0.8% e totalmente ausente com o E80%. Quanto à avaliação referente aos segmentos da parede aórtica, também evidenciou-se progressiva calcificação, não sendo inibidas pelos tratamentos com AG 0.8% e E80%. Conclusões: Concluiu-se que o pré-tratamento com etanol a 80% inibiu a calcificação nas cúspides aórticas porcinas, entretanto não teve a mesma eficácia na parede aórtica. Contudo, o ácido L-glutâmico a 0.8% demonstrou minimizar a calcificação na parede aórtica. Estudos devem ser feitos para evidenciar se a ação anticalcificante do etanol a 80% mantém-se em as biopróteses aórticas porcinas forem implantadas no sistema circulatório.
Palabras clave
Cúspide porcina, etanol, calcificação, parede aórtica porcina, ácido L-glutâmico
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Especialidades
Principal: Cardiología
Relacionadas: Medicina Interna
Patrocinio y reconocimiento
Trabalho realizado no Departamento de Cirurgia Experimental da Disciplina de Técnica Operatória da Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brasil
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COMPARATIVE STUDY ON THE EFFICACY OF ETHANOL AND L-GLUTAMIC ACID FOR PREVENTING CALCIFICATION OF PIG CUSPS AND AORTIC WALL. EXPERIMENTAL STUDY IN RATS
Abstract
Introduction: The glutataldehyde (GDA) treated pigs cusps are one of most employed tissues in bioprothesis, but its late post-implant calcification is the main cause of its failure. Background: This study aims at comparing and analyzing two methods (ethanol 80% and l-glutamic acid 0.8%) to prevent calcification in pig cusps and aortic wall implanted subcutaneously in rats, the cusps and aortic wall segments of the controls were fixed with glutaraldehyde (GDA), during a 15, 30 and 60 days after the implant. Material and Methods: We used 45 young rats, distributed in 3 groups of 15 rats each, which were subdivided in 3 subgroups of 5 rats each, in which we implanted one cusp and one aortic wall segment in 2 subcutaneous pouches for each rat. We called each group as follows: GDA (control group), E80% (the group whose structures were previously prepared with ethanol 80%) and GA 0.8% (group previously prepared with L-glutamic acid 0.8%); in those groups we measured calcium and performed a microscopic analysis seeking for any calcification, its location and intensity; inflammatory infiltrate, location and type, during a 15, 30. and 60-day period after the implant. Results: Calcium was found in the aortic cusp in the E80% group (1.30 ± 0.21 μg calcium/mg tissue) at day 15, (1.05 ± 0.22 μg calcium/mg tissue) at day 30. and (0.53 ± 0.42 μg calcium/mg tissue) at day 60; in the GA 0.8% group (12.17 ± 0.66 μg calcium/mg tissue) at day 15, (15.31 ± 2.82 μg calcium/mg tissue) at day 30. and (34.24 ± 16.28 μg calcium/mg tissue) at day 60; and in the control group, GDA at day 15 (12.44 ± 2.26 μg calcium/mg tissue), at day 30 (13.44 ± 3.34 μg calcium/mg tissue), and at day 60 (50.85 ± 8.71 μg calcium/mg tissue). As for the calcium measured in the aortic wall, in the E80% group we found (4.62 ± 0.68 μg calcium/mg tissue) at day 15, (9.47 ± 2.59 μg calcium/mg tissue) at day 30. and (23.56 ± 7.75 μg calcium/mg tissue) at day 60; in the GA 0.8% group at day 15 (4.31 ± 0.85 μg calcium/mg tissue), at day 30 (7.69 ± 1.48 μg calcium/mg tissue), and at day 60 (20.50 ± 1.22 μg calcium/mg tissue); and in the control group (GDA) at day 15 (7.34 ± 1.32 μg calcium/mg tissue), at day 30 (9.28 ± 0.76 μg calcium/mg tissue), at day 60 (27.60 ± 1.08 μg calcium/mg tissue). Microscopic evaluation of the aortic cusp, showed a progressive calcification in those fixed with GDA. Such process was found partially in the GA 0.8% group, and totally absent in the E80% group. As for the assessment of the aortic wall segments, we also observed progressive calcification, which was not inhibited by the treatment with either GA 0.8% or E80%. Conclusions: We concluded that a pre-treatment with ethanol at 80% inhibited calcification in pig aortic cusps, however it was not as effective on the aortic wall. However, L-glutamic acid at 0.8% did show that it minimizes calcification in the aortic wall. Further studies are required, to demonstrate if the anti-calcifying action of ethanol at 80% is kept if the pig aortic bioprostheses are implanted in the circulatory system.
Key words
Descriptors: pig aortic cusp, calcification, ethanol, pig aortic wall, l-glutamic acid
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