Inflammatory and immune processes: the neglected villain of bioprosthetic degeneration?
In an attempt to avoid the destructive process of bioprosthetic heart-valve calcification associated with the use of glutaraldehyde, valves are today prepared using low concentrations of the crosslinking reagent. In this review, we summarize our findings and those of others that confirm that the immunogenicity of such tissue is not sufficiently masked and that a defined humoral response is indeed mounted against a repertoire of antigens unrelated to those associated with vascularized and non-cross-linked xenograft organs. We demonstrate the need for increased cross-linking of tissue to satisfactorily mitigate that response; furthermore, we examine the impact of increased cross-link density on the macrophage as antigen presenting cell with respect to its involvement in both tissue erosion and pannus overgrowth. Finally we present evidence for a role of circulating antibodies in bioprosthesis calcification.
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Department of Cardiothoracic Surgery, Cape Heart Centre, University of Cape Town Medical School, Cape Town, South Africa.
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D000818:Animals; D017951:Antigen Presentation; D001705:Bioprosthesis / Q000009:adverse effects*; D002114:Calcinosis / Q000276:immunology* / Q000517:prevention & control*; D003432:Cross-Linking Reagents / Q000378:metabolism; D005404:Fixatives / Q000009:adverse effects; D005549:Foreign-Body Reaction / Q000276:immunology; D005976:Glutaral / Q000009:adverse effects; D006085:Graft Survival / Q000276:immunology*; D006349:Heart Valve Diseases / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000517:prevention & control; D008264:Macrophages / Q000276:immunology
D003432:Cross-Linking Reagents; D005404:Fixatives; D005976:Glutaral