title: Requirement for vitamin A in long-term culture of human cornea.
abstract: OBJECTIVE
  To develop an in vitro model for the study of vitamin A functions in the cornea by determining the morphologic responses to its absence and to the addition of varying concentrations in long-term (21-day) human organ culture.
  
  
  METHODS
  Donor corneas were cultured for 21 days in an air-liquid environment designed to maintain normal corneal morphology in long-term culture. Corneas were graded by light microscopy and were further analyzed by transmission electron microscopy.
  
  
  RESULTS
  Epithelium of human corneas cultured in the absence of vitamin A for 21 days showed characteristics of vitamin A deficiency: multilayering of squamous cells, bundling of tonofilaments to form keratofibrils, increased desmosomes, and loss of microplicae on the surface cells. The cells responded to the addition of vitamin A in concentrations ranging from 5 x 10(-9) to 5 x 10(-6) M. At the lowest concentration, cell differentiation and morphology appeared normal. Cells developed secretory morphology at higher concentrations of vitamin A, with intracellular vesicles, basement membrane overproduction, and reduced cell-cell and cell-substrate attachments. Keratocytes and endothelial cells showed increased intracellular vacuoles in the presence of higher concentrations of vitamin A.
  
  
  CONCLUSIONS
  Cultured adult human corneas showed primary, dose-related responses to vitamin A in the absence of inflammatory, neuronal, or humoral factors. The epithelium was most sensitive to the absence of vitamin A and showed a dose-related response to additional vitamin A. All corneal cell layers showed morphologic changes at the highest concentration of vitamin A used.
authors.affiliation: National Vision Research Institute, Sharp Cabrillo Hospital, San Diego, California 92103.
authors.forename: J A
authors.initials: JA
authors.lastname: Anderson
authors.forename: N R
authors.initials: NR
authors.lastname: Richard
authors.forename: M E
authors.initials: ME
authors.lastname: Rock
authors.forename: P S
authors.initials: PS
authors.lastname: Binder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001485:Basement Membrane / Q000648:ultrastructure; D002454:Cell Differentiation; D002455:Cell Division; D003315:Cornea / Q000187:drug effects / Q000648:ultrastructure*; D003319:Corneal Stroma / Q000648:ultrastructure; D016895:Culture Media, Serum-Free; D004728:Endothelium, Corneal / Q000648:ultrastructure; D004848:Epithelium / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009924:Organ Culture Techniques; D014801:Vitamin A / Q000494:pharmacology / Q000502:physiology*
chemical_list: D016895:Culture Media, Serum-Free; D014801:Vitamin A