Ácido L-glutâmico na prevenção da calcificação de pericárdio bovino fixado em glutaraldeído: estudo em ratos

Abstract

RBCCV 44205-905Ácido L-glutâmico na prevenção da calcificação de pericárdio bovino fixado em glutaraldeído: estudo em ratos L-glutamic acid in the prevention of the calcification of bovine pericardial fixed in glutaraldehyde: study in rats Abstract Objective: To evaluate the efficiency of L-glutamic acid to prevent calcification of glutaraldehyde bovine pericardium implanted in rats' subcutaneous tissues.Methods: Fifty four Wistar rats were divided in six groups according to the type of the bovine pericardium implanted. At first, all pericardia were initially cross-linked with 0.5% glutaraldehyde (GDA) fixative for 72 h. In Group I, after the initial fixation, the pericardia were preserved in 0.2% GDA fixative until the implantation, whereas in Group II they were stocked in Paraben solution. In Groups III and IV, after the initial fixation in 0.5% GDA fixative, the pericardia were treated with 8% L-glutamic acid at pH 7.4 and 3.5, respectivelly, being subsequently stocked in Paraben solution. Groups V and VI were similar to III and IV, except for the concentration of L-Glutamic acid which was 0.8%. Explantation was done at 15, 30, and 60 days, and the specimens submitted to histological analysis with Hematoxylin and eosin (HE) and Von Kossa stains, besides calcium quantification with atomic spectrofotometry.Results: Microscopic analysis demonstrated severe and progressive calcification in groups I, II, and III, whereas in groups IV, V, and VI calcification, when present, was mild and focal. Spectrofotomety confirmed these findings, revealing calcium contents of 1.93µg/mg of tissue at 60 days in the control group. Groups IV and VI showed the least calcium contents (0.063 e 0.066, respectively).Conclusions: The use of L-glutamic acid in segments of bovine pericardium with glutaraldehyde fixative was effective in preventing the calcification when implanted in rats' subcutaneous tissues up to 60 days.Descriptors: Glutamic acid. Glutaral. Pericardium. Calcinosis. 304FERREIRA, ADA ET AL -L-glutamic acid in the prevention of the calcification of bovine pericardial fixed in glutaraldehyde: study in rats Bras Cir Cardiovasc 2007; 22(3): 303-309 particularly in developing countries, in which the usage of the biological prostheses is more frequent. RevThe aim of the present study was to analyze the efficacy of L-glutamic acid in concentrations of 0.8% and 8%, pH values ranging from 3.5 (acid) to 7.4 (physiologic), in the prevention of the segments calcification of the bovine pericardium with glutaraldehyde fixative and implanted in the subcutaneous tissue of young rats. METHODSThis study was carried out at the following Labs:

Efeito da descelularização com SDS na prevenção da calcificação em pericárdio bovino fixado em glutaraldeído

“…Treatment with glutamic acid reduced the amount of calcium in the control group, which had been documented by Ferreira et al [12]. Moreover, the study of Jorge-Herrero et al [8] glutamic acid was not as effective and, paradoxically, the pericardium treated behaved worse than the control group.…”

“…Preliminary study of our research group, using the same experimental model used here, has shown that glutamic acid was effective in reducing the calcification of bovine pericardium fixed in glutaraldehyde [12]. For this reason, fixed in glutaraldehyde bovine pericardium formed our control group, whereas the addition of decellularization or post-treatment were compared with glutamic acid alone or in combination to determine the most efficient way to reduce calcification.…”

“…In an attempt to eliminate or delay this complication, several anti-calcification methods were tested, with varying degrees of success [5]. These methods aim primarily to remove the calcifying components of the tissue or neutralize the toxic effects of residual aldehydes [6][7][8][9][10][11][12].…”

Descelularização como método anticalcificante em próteses valvares de pericárdio bovino sem suporte

“…Most studies used the implant model in TCSC of rats, which limits its interpretation because it does not assess the influence of bloodstream and tissue stress effects on calcification [12,13,15,16,21]. Our research group evaluated the effect of SDS decellularization in GDA-fixed bovine pericardium and implanted in the TCSC of rats for 90 days, with a reduction of 98% in the final amount of calcium (65.91 µg/mg tissue versus 1.24 µg/mg tissue) (unpublished data).…”

“…Several treatments were tested in order to eliminate or retard the calcification, but no method is quite effective yet [12][13][14][15][16]. The decellularization has been proposed as an alternative during the biological tissue processing of cardiovascular prostheses.…”