title: [Is chronic graft rejection the reason for degenerative changes in allogeneic and xenogeneic heart valve prostheses: immunohistochemical evaluation of inflammatory factors].
abstract: OBJECTIVE
  After a period of 5 to 10 years, biological heart valve prostheses undergo degenerative processes, which finally lead to dysfunction and complete destruction. Although many efforts have been made to identify underlying mechanisms, many questions remain unanswered. Here we evaluate immunological factors and their potential role in biological heart valve destruction.
  
  
  METHODS
  Allogeneic (n=10) and xenogeneic (n=3) aortic valvular prostheses, as well as aortic valves retrieved from transplanted human hearts, which had to be replaced because of chronic graft rejection (n=4) were analyzed. Aortic valves from human donor hearts (native) (n=4), which were considered not transplantable served as controls. Endothelial expression patterns of the following adhesion molecules were analyzed by immunohistochemistry: selectin family: ELAM-1, CD62, integrin family: VLA-1, -2, -3, -4, -5, and -6, immunoglobulin supergene family: PECAM-1, ICAM-1, and -2, and class I heavy chain proteins, complementary adhesion molecules: CD34, CD44 and the von Willebrand factor.
  
  
  RESULTS
  ELAM-1, ICAM-1 and -2, CD34, CD44 and class I heavy chain proteins, all molecules which play significant roles during inflammatory processes, showed stronger expression patterns in allogeneic and xenogeneic aortic heart valve prostheses compared to native or chronically rejected valves. Furthermore, the von Willebrand factor stained positive only on allogeneic and xenogeneic valves. Only mild differences were observed regarding the expression of integrin molecules and CD62.
  
  
  CONCLUSIONS
  Immunological reactions play a major role in the degeneration of biological heart valve prostheses. This is underlined by observations made on aortic valves from chronically rejected cardiac grafts, which did not show any degenerative alterations. Thus, since immunosuppressive therapy after heart valve replacement is no reasonable alternative, novel and future approaches in "tissue engineering" will hopefully help avoid tissue degeneration, while preserving the advantage of biological tissue origin.
authors.affiliation: Abt. f. Thorax, Herz und Gefässchirurgie Medizinische Hochschule Hannover Carl-Neuberg-Strasse 1 30627 Hannover, Germany. Wilhelmi@thg.mh-hannover.de
authors.forename: Mathias
authors.initials: M
authors.lastname: Wilhelmi
authors.forename: Stefan
authors.initials: S
authors.lastname: Fischer
authors.forename: Heike
authors.initials: H
authors.lastname: Mertsching
authors.forename: Rainer
authors.initials: R
authors.lastname: Leyh
authors.forename: Matthias
authors.initials: M
authors.lastname: Karck
authors.forename: Axel
authors.initials: A
authors.lastname: Haverich
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000473:pathology* / Q000637:transplantation*; D015815:Cell Adhesion Molecules; D002908:Chronic Disease; D006084:Graft Rejection / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology; D016023:Integrins / Q000032:analysis; D013552:Swine; D013997:Time Factors; D014019:Tissue Donors; D014181:Transplantation Immunology; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous
chemical_list: D015815:Cell Adhesion Molecules; D016023:Integrins