title: Characterization of porcine corneal endothelium for xenotransplantation.
abstract: OBJECTIVE
  Endothelial keratoplasty (EKP) has become increasingly popular in the treatment of corneal disease. However, the global shortage of human donor corneas limits clinical corneal transplantation. Genetically engineered (GE) pigs may provide an alternative source of corneas for EKP. The aim of this study was to evaluate corneal endothelial cells (CECs) from wild-type (WT) and GE pigs.
  
  
  METHODS
  Density, size of CECs, and the percentage of hexagonal cells (as a measure of heterogeneity) were measured by ex vivo confocal microscopy in corneas from WT and GE pigs of different ages - neonatal (4-5 days), young (5-15 weeks), adult (5-15 months), and old (20-42 months). α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for the human complement-regulatory protein(s), CD46 (GTKO/CD46) +/- CD55 (GTKO/CD46/CD55) were used as sources of GE corneas.
  
  
  RESULTS
  Mean CEC densities (cells/mm²) were neonatal (5968), young (3789), adult (2589), and old (2070). As with human corneas, there was an age-dependent decrease in pig CEC density and increase in pig CEC size. However, unlike human corneas, there was no correlation between the percentage of hexagonal cells (approximately 50% in all pig corneas) and age, suggesting that heterogeneity is intrinsic for pig corneas. Genetic modification did not affect CEC density, size, or morphology compared to WT pigs.
  
  
  CONCLUSIONS
  Because of the availability of young pigs and their greater CEC density (and the protection afforded against the human immune response), GE pigs could provide an unlimited source of corneas for clinical EKP.
authors.affiliation: Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh , Pittsburgh, Pennsylvania , USA .
authors.forename: Seung Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Ruhina
authors.initials: R
authors.lastname: Mehra
authors.forename: Minoru
authors.initials: M
authors.lastname: Fujita
authors.forename: Danny S
authors.initials: DS
authors.lastname: Roh
authors.forename: Cassandra
authors.initials: C
authors.lastname: Long
authors.forename: Whayoung
authors.initials: W
authors.lastname: Lee
authors.forename: James L
authors.initials: JL
authors.lastname: Funderburgh
authors.forename: David L
authors.initials: DL
authors.lastname: Ayares
authors.forename: David K C
authors.initials: DK
authors.lastname: Cooper
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hara
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D018958:CD55 Antigens / Q000235:genetics / Q000378:metabolism; D002452:Cell Count; D048429:Cell Size; D016039:Corneal Transplantation; D004728:Endothelium, Corneal / Q000166:cytology* / Q000378:metabolism; D005700:Galactosyltransferases / Q000235:genetics / Q000378:metabolism; D055786:Gene Knockout Techniques; D008253:Macaca mulatta; D051916:Membrane Cofactor Protein / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D013552:Swine / Q000235:genetics*; D014183:Transplantation, Heterologous
chemical_list: D018958:CD55 Antigens; D051916:Membrane Cofactor Protein; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase