title: Changes in human donor corneas preserved for longer than 4 weeks.
abstract: OBJECTIVE
  Corneas are usually stored for a maximum of approximately 30 days in European cornea banks. Although attempts are being made to prolong culture periods, data on their success are extremely limited to date. The following study was carried out to describe the capacities and limits of the established system.
  
  
  METHODS
  Thirty-seven human corneas were stored for < or = 12 weeks under standard eye bank conditions [modified minimal essential medium (MEM), 31 degrees C, closed system]. Twenty-one fresh human corneas served as control. Both the adenylate nucleotides and the glucose and lactate concentrations were measured in the tissue (all cellular layers) by using the bioluminescence technique. The endothelial-cell densities also were determined.
  
  
  RESULTS
  Endothelial-cell densities decreased from 2,963.4 +/- 58.7 cells/mm2 (fresh) to 2,649 cell/mm2 after 4 weeks and to 2,087 cells/mm2 after 6 weeks. Storage for periods >6 weeks led to total endothelial necrosis. Biochemical studies showed improving values during the first 4 weeks and acceptable conditions for < or = 6 weeks.
  
  
  CONCLUSIONS
  From these data, we conclude that long-term organ culture in a closed system is limited to approximately 6 weeks and thereby confirm the clinical results of Früh and Böhnke.
authors.affiliation: Department of Ophthalmology, RWTH Aachen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Redbrake
authors.forename: S
authors.initials: S
authors.lastname: Salla
authors.forename: A
authors.initials: A
authors.lastname: Frantz
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D002452:Cell Count; D003315:Cornea / Q000378:metabolism* / Q000473:pathology; D004728:Endothelium, Corneal / Q000473:pathology; D005125:Eye Banks; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007785:Lactose / Q000378:metabolism; D009924:Organ Culture Techniques / Q000379:methods; D009926:Organ Preservation; D013997:Time Factors; D014019:Tissue Donors
chemical_list: D000227:Adenine Nucleotides; D005947:Glucose; D007785:Lactose