title: Glucose permeability of human, bovine, and porcine corneas in vitro.
abstract: OBJECTIVE
  To measure glucose flux across human, bovine, and porcine corneas and to determine the diffusion coefficient of each type of cornea.
  
  
  METHODS
  Diffusion of glucose across human (n = 8), bovine (n = 7), and pig corneas (n = 8) was measured using a modified blind well chamber apparatus (Boyden chamber). Dialysis membranes (n = 7) and nonporous Mylar membranes (n = 7) were used as positive and negative controls, respectively. Glucose concentrations were measured at 30-min intervals with a commercially available glucose meter.
  
  
  RESULTS
  The diffusion of glucose through corneas in vitro was calculated by a simple Fickian diffusion model. The diffusion coefficient of glucose is highest for the human cornea (D(HC) = 3.0 +/- 0.2 x 10(-6) cm(2)/s) followed by porcine corneas (D(PC) = 1.8 +/- 0.6 x 10(-6) cm(2)/s) and bovine corneas (D(BC) = 1.6 +/- 0.1 x 10(-6) cm(2)/s) (p < 0.05). The diffusion coefficients of all tested corneas were significantly higher (p < 0.05) than that of dialysis membrane (D(DM) = 3.4 +/- 0.2 x 10(-7) cm(2)/s).
  
  
  CONCLUSIONS
  The glucose diffusion coefficients of human, bovine, and porcine corneas are on the order of 10(-6). Human corneas have higher permeability to glucose than either porcine or bovine corneas.
authors.affiliation: Department of Ophthalmology, Stanford University, Stanford, Calif., USA.
authors.forename: David
authors.initials: D
authors.lastname: Myung
authors.forename: Kristen
authors.initials: K
authors.lastname: Derr
authors.forename: Philip
authors.initials: P
authors.lastname: Huie
authors.forename: Jaan
authors.initials: J
authors.lastname: Noolandi
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Ta
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Ta
mesh_terms: D000818:Animals; D001692:Biological Transport; D002417:Cattle; D003315:Cornea / Q000378:metabolism*; D004058:Diffusion; D015194:Diffusion Chambers, Culture; D005947:Glucose / Q000493:pharmacokinetics*; D006801:Humans; D010539:Permeability; D013552:Swine
chemical_list: D005947:Glucose