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NEW ALPHA-GAL REMOVAL ASSAY: PRESENCE AND DISTRIBUTION OF THE EPITOPE BEFORE AND AFTER CELL REMOVAL FROM XENOGENEIC HEART VALVES
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First quantitative assay of alpha-Gal in soft tissues: presence and distribution of the epitope before and after cell removal from xenogeneic heart valves.
No full textDecellularized xenograft heart valves might be the ideal scaffolds for tissue engineered heart valves as the alternative to the currently used biological and mechanical prostheses. However, removal of the alpha-Gal epitope is a prerequisite to avoid hyperacute rejection of untreated xenograft material. The aim of this study was to develop an ELISA soft-tissue assay for alpha-Gal quantification in xenograft heart valves before and after a detergent-based (TriCol) or equivalent cell removal procedure. Leaflets from porcine valves were enzymatically digested to expose the epitope and reacted with the alpha-Gal monoclonal antibody M86 for its recognition. Rabbit erythrocytes were used as a reference for the quantification of alpha-Gal. Native aortic and pulmonary leaflets exhibited different epitope concentration: 4.33×10(11) vs. 7.12×10(11)/10 mg wet tissue (p<0.0001). Sampling of selected zones in native valves revealed a different alpha-Gal distribution within and among different leaflets. The pattern was consistent with immunofluorescence analysis and was unrelated to microvessel density distribution. After TriCol treatment alpha-Gal was no longer detectable in both pulmonary and aortic decellularized valves, confirming the ability of this method to remove both cells and alpha-Gal antigen. These results hold promise for a reliable quantitative evaluation of alpha-Gal in decellularized valves obtained from xenograft material for tissues engineering purposes. Additionally, this method is applicable to further evaluate currently used xenograft bioprostheses
QUANTITATIVE EVALUATION OF THE ALPHA-GAL XENOANTIGEN IN CURRENTLY HEART VALVE BIOPROSTHESES. COMPARISON WITH THE ALPHA-GAL AMOUNT IN THE ORIGINAL TISSUES UTILIZED FOR THEIR FABRICATION BEFORE AND AFTER DIFFERENT DECELLULARIZATION PROCEDURE
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Alpha-Gal detectors in xenotransplantation research: a word of caution.
No full textXenogeneic tissues are currently employed in clinical practice to create biological substitutes (bioprosthetic heart valves) and in the repair of various damaged tissues (pericardium, gastric-mucosa, nerves, cartilage). Many studies have shown that xenogeneic tissues express superficial epitopes as alpha-Gal, capable of triggering hyperacute and acute vascular rejection phenomena. Currently, no tissue treatment has proven able to completely mask or inactivate such epitopes. In fact, neither glutaraldehyde fixation nor decellularisation procedures ensure a definitive solution because of the persistence of reactive xenoantigen residues. The ability to ascertain alpha-Gal epitope removal from a xenogeneic tissue is closely related to the possibility of its quantitative determination. In the past, detection of the alpha-Gal epitope relied on the use of alpha-Gal reactive isolectin molecules and was limited to isolated cells. Recently, the quantitative evaluation of this antigen has been carried out in whole connective tissue through the use of the monoclonal antibody M86. This article provides an overview of the implications of the alpha-Gal epitope in the current clinical scenario and a definitive comparison between the reliability and specificity of isolectines vs. M86 in alpha-Gal determination
FLOGISTIC AND BIOCOMPATIBILITY EFFECTS DETERMINATION OF DECELLULARIZED AND COMMERCIAL AVAILABLE AORTIC LEAFLETS AFTER IMPLANTATION IN A PERITONEAL EXPERIMENTAL RAT MODEL
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Synthetic peptides for heart valve tissue engineering:smooth muscle cells adhesion tests
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