title: Quality assessment of corneal storage media and their components.
abstract: BACKGROUND
  To keep the loss of endothelial cell density in donor corneas to a minimum, a storage medium which is adjusted to their nutritional needs is necessary. Different media, used either serum-supplemented or serum-free, are available. The quality of medium- and serum-batches as well as support of endothelial cell viability by the medium are to be tested with a quality assured screening system that allows routine examination.
  
  
  METHODS
  A screening system was developed which is based on cell-culture tests with the well-established human corneal endothelial cell line HCEC-12, and therefore can be performed without the need for donor corneas. The cells are plated at a defined density in cell-culture dishes, and are cultured for a defined period of time in the test media. Evaluation is carried out by assaying cell count, activity of cell metabolism (resazurin conversion), and determining the number of apoptotic and necrotic cells (combined vital staining with YO-PRO®-1/propidium iodide and subsequent flow cytometry).
  
  
  RESULTS
  Human corneal endothelial cells that are cultured in a medium which is adjusted to their nutritional needs achieve higher cell numbers and show a higher metabolic rate. Simultaneously, the percentage of apoptotic and necrotic cells is lower. The screening system developed in this study allows for easy and reliable detection of slightest differences between different media, different processing steps for same media, and different supplements, as well as different serum batches.
  
  
  CONCLUSIONS
  The differentiated results show that the screening system is sensitive enough to show even minor quality differences. Therefore, it is more suitable than the hitherto commonly used growth assay with primary, mostly porcine, corneal endothelial cells.
authors.affiliation: Coating of Flat Substrates, Medicine-Technical Application, Fraunhofer Institute for Electron Beam and Plasma Technology FEP, Winterbergstrasse 28, 01277, Dresden, Germany, jessy.schoenfelder@fep.fraunhofer.de.
authors.forename: Jessy
authors.initials: J
authors.lastname: Schönfelder
authors.forename: Monika
authors.initials: M
authors.lastname: Valtink
authors.forename: Lilla
authors.initials: L
authors.lastname: Knels
authors.forename: Richard H W
authors.initials: RH
authors.lastname: Funk
authors.forename: Katrin
authors.initials: K
authors.lastname: Engelmann
authors.forename: Christiane
authors.initials: C
authors.lastname: Wetzel
mesh_terms: D017209:Apoptosis; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D003470:Culture Media; D016895:Culture Media, Serum-Free / Q000494:pharmacology*; D004728:Endothelium, Corneal / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007202:Indicators and Reagents / Q000378:metabolism; D009336:Necrosis; D009924:Organ Culture Techniques; D019188:Organ Preservation Solutions / Q000494:pharmacology*; D010078:Oxazines / Q000378:metabolism; D014966:Xanthenes / Q000378:metabolism
chemical_list: D003470:Culture Media; D016895:Culture Media, Serum-Free; D007202:Indicators and Reagents; D019188:Organ Preservation Solutions; D010078:Oxazines; D014966:Xanthenes; C005843:resazurin