title: Effect of high glucose on permeability of retinal capillary endothelium in vitro.
abstract: OBJECTIVE
  To study the effect of high glucose on the permeability of bovine retinal capillary endothelial cell (BRCEC) monolayers.
  
  
  METHODS
  The paracellular permeability of second-passage BRCEC cultured on millipore filters in two chamber transwell inserts was assayed by measuring the peak trans-monolayer electrical resistance and percent equilibration of 14C-inulin 48 hours after it had been added to the luminal chamber.
  
  
  RESULTS
  High glucose increased the paracellular permeability of BRCEC monolayers independently of its hypertonic action (5 mM glucose: 154.2 +/- 21.2 and 19.5 +/- 2.4; 30 mM glucose: 134.2 +/- 5.1 [P = 0.01] and 23.5 +/- 2.1 [P = 0.01]; 5 mM glucose + 25 mM mannitol: 168.7 +/- 13.7 ohm.cm2 [P = 0.04] and 19.3% +/- 1.2% 48-hour equilibration of inulin [P = 0.008]). In a separate series of experiments, the authors were unable to show that either aminoguanidine or ponalrestat prevented the effect of high glucose on permeability (30 mM glucose 95.1 +/- 16.7 and 45.4 +/- 5.6; 5 mM glucose: 122.9 +/- 14.2 [P = 0.02] and 36.6 +/- 5.6 [P = 0.001]; 30 mM glucose + aminoguanidine 87.9 +/- 17.5 [P = 0.04] and 75.3 +/- 14.9 [P = 0.6]; 30 mM glucose + ponalrestat 79.9 +/- 12.7 ohm.cm2 [P = 0.1] and 48.2 +/- 2.5% 48-hour equilibration of inulin [P = 0.15]). Ponalrestat did not abrogate the effect of high glucose despite its ability to reduce a high glucose-induced increase in BRCEC intracellular sorbitol levels.
  
  
  CONCLUSIONS
  The data are consistent with a role for increased paracellular permeability in breakdown of the blood-retinal barrier in diabetic retinopathy, which appears to be independent of both nonenzymatic glycosylation and the polyol pathway.
authors.affiliation: Department of Ophtalmology, Sydney University, Australia.
authors.forename: M C
authors.initials: MC
authors.lastname: Gillies
authors.forename: T
authors.initials: T
authors.lastname: Su
authors.forename: J
authors.initials: J
authors.lastname: Stayt
authors.forename: J M
authors.initials: JM
authors.lastname: Simpson
authors.forename: D
authors.initials: D
authors.lastname: Naidoo
authors.forename: C
authors.initials: C
authors.lastname: Salonikas
mesh_terms: D000818:Animals; D001813:Blood-Retinal Barrier; D002199:Capillary Permeability / Q000187:drug effects*; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002417:Cattle; D002478:Cells, Cultured; D015194:Diffusion Chambers, Culture; D017097:Electric Impedance; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D006146:Guanidines / Q000494:pharmacology; D007444:Inulin / Q000493:pharmacokinetics*; D019344:Lactic Acid / Q000378:metabolism; D010793:Phthalazines / Q000494:pharmacology; D011108:Polymers / Q000378:metabolism; D019289:Pyruvic Acid / Q000378:metabolism; D012171:Retinal Vessels / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013012:Sorbitol / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; D006146:Guanidines; D010793:Phthalazines; D011108:Polymers; C024617:polyol; C042829:ponalrestat; D005632:Fructose; D019344:Lactic Acid; D013012:Sorbitol; D019289:Pyruvic Acid; D007444:Inulin; D005947:Glucose; C004479:pimagedine