title: Antibody formation towards porcine tissue in patients implanted with crosslinked heart valves is directed to antigenic tissue proteins and αGal epitopes and is reduced in healthy vegetarian subjects.
abstract: Glutaraldehyde-fixed porcine heart valves (ga-pV) are one of the most frequently used substitutes for insufficient aortic and pulmonary heart valves which, however, degenerate after 10-15 years. Yet, xeno-immunogenicity of ga-pV in humans including identification of immunogens still needs to be investigated. We here determined the immunogenicity of ga-pV in patients with respect to antibody formation, identity of immunogens and potential options to reduce antibody levels.
  
  
  
  Levels of tissue-specific and anti-αGal antibodies were determined retrospectively in patients who received ga-pV for 51 months (n=4), 25 months (n=6) or 5 months (n=4) and compared to age-matched untreated subjects (n=10) or younger subjects with or without vegetarian diet (n=12/15). Immunogenic proteins were investigated by Western blot approaches.
  
  
  
  Tissue-specific antibodies in patients were elevated after 5 (1.73-fold) and 25 (1.46-fold, both P<.0001) months but not after 51 months, whereas anti-Gal antibodies were induced 4.75-fold and 3.66-fold after 5 and 25 months (both P<.0001) and still were significantly elevated after 51 months (2.85-fold, P<.05). Western blots of porcine valve extracts with and without enzymatic deglycosylation revealed strong specific staining at ≈65 and ≈140 kDa by patient sera in either group which were identified by 2D Western blots and mass spectrometry as serum albumin and collagen 6A1. Vegetarian diet reduced significantly (0.63-fold, P<.01) the level of pre-formed αGal but not of tissue-specific antibodies.
  
  
  
  Immune response in patients towards ga-pV is induced by the porcine proteins albumin and collagen 6A1 as well as αGal epitopes, which seemed to be more sustained. In contrast, in healthy young subjects pre-formed anti-Gal antibodies were reduced by a meat-free nutrition.
authors.affiliation: Lower Saxony Centre of Biotechnology Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany.|Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Ulrike
authors.identifier: 0000-0003-0861-5125
authors.initials: U
authors.lastname: Böer
authors.affiliation: Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany.
authors.forename: Falk F R
authors.initials: FFR
authors.lastname: Buettner
authors.affiliation: Lower Saxony Centre of Biotechnology Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany.
authors.forename: Ariane
authors.initials: A
authors.lastname: Schridde
authors.affiliation: Lower Saxony Centre of Biotechnology Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany.|Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Klingenberg
authors.affiliation: Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Samir
authors.initials: S
authors.lastname: Sarikouch
authors.affiliation: Lower Saxony Centre of Biotechnology Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany.|Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Haverich
authors.affiliation: Lower Saxony Centre of Biotechnology Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany.|Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Wilhelmi
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005976:Glutaral / Q000494:pharmacology*; D006084:Graft Rejection / Q000276:immunology*; D006351:Heart Valves / Q000187:drug effects / Q000276:immunology* / Q000637:transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013552:Swine; D014183:Transplantation, Heterologous / Q000379:methods; D000066988:Vegetarians; D000519:alpha-Galactosidase / Q000276:immunology*
chemical_list: D000906:Antibodies; D000939:Epitopes; D000519:alpha-Galactosidase; D005976:Glutaral
keywords: bioartificial heart valve; crosslinking; immunogenic proteins; mass spectrometry; vegetarian diet; αGal epitope, antibody formation