title: A comparison of three methods of decellularization of pig corneas to reduce immunogenicity.
abstract: OBJECTIVE
  To investigate whether decellularization using different techniques can reduce immunogenicity of the cornea, and to explore the decellularized cornea as a scaffold for cultured corneal endothelial cells (CECs). Transplantation of decellularized porcine corneas increases graft transparency and survival for longer periods compared with fresh grafts.
  
  
  METHODS
  Six-month-old wild-type pig corneas were cut into 100-200 µm thickness, and then decellularized by three different methods: 1) 0.1% sodium dodecyl sulfate (SDS); 2) hypoxic nitrogen (N2); and 3) hypertonic NaCl. Thickness and transparency were assessed visually. Fresh and decellularized corneas were stained with hematoxylin/eosin (H&E), and for the presence of galactose-α1,3-galactose (Gal) and N-glycolylneuraminic acid (NeuGc, a nonGal antigen). Also, a human IgM/IgG binding assay was performed. Cultured porcine CECs were seeded on the surface of the decellularized cornea and examined after H&E staining.
  
  
  RESULTS
  All three methods of decellularization reduced the number of keratocytes in the stromal tissue by >80% while the collagen structure remained preserved. No remaining nuclei stained positive for Gal or NeuGc, and expression of these oligosaccharides on collagen was also greatly decreased compared to expression on fresh corneas. Human IgM/IgG binding to decellularized corneal tissue was considerably reduced compared to fresh corneal tissue. The cultured CECs formed a confluent monolayer on the surface of decellularized tissue.
  
  
  CONCLUSIONS
  Though incomplete, the significant reduction in the cellular component of the decellularized cornea should be associated with a significantly reduced in vivo immune response compared to fresh corneas.
authors.affiliation: Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Whayoung
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Miyagawa
authors.affiliation: Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Long
authors.affiliation: Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: David K C
authors.initials: DK
authors.lastname: Cooper
authors.affiliation: Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hara
keywords: cornea; decellularization; immune response; pig; xenotransplantation