Physiological transport properties of cultured retinal microvascular endothelial cell monolayers.
OBJECTIVE
To characterize baseline transport properties: hydraulic conductivity (Lp), albumin permeability (Pe), and transendothelial electrical resistance (TER) of bovine retinal microvascular endothelial cells (RMEC) in the development of an in vitro model of the blood-retinal barrier (BRB).


METHODS
RMEC were grown on porous, polycarbonate filters for determination of the number of days required to achieve minimal transport rates. Lp, Pe, and TER were measured by utilizing a bubble tracking spectrophotometer, by quantifying the diffusional movement of fluorescein isothiocyanate-labeled albumin, and by utilizing a Millipore electrical resistance meter, respectively.


RESULTS
Lp decreased significantly from 7.82 +/- 0.85 x 10(-7) (mean +/- SEM) cm/sec/cm H2O at post-plating Day 5 to 1.44 +/- 0.26 x 10(-7) cm/sec/cm H2O at Day 9. Pe of the monolayer also decreased progressively with days post-plating from 3.44 +/- 0.53 x 10(-6) cm/sec at Day 7 to a minimum of 1.95 +/- 0.29 x 10(-6) cm/sec at Day II. Peak TER fluctuated until Day 7, when it began to steadily increase from 17.14 ohm-cm2 to a peak value of 25.42 ohm-cm2 at Day 10, decreasing from then on to 22.24 ohm.cm2 on Day 12. Known disrupters of the BRB, NECA and VEGF, elicited significant increase in RMEC Lp showing the sensitivity of this model to pharmacological alterations.


CONCLUSIONS
Our data indicate that RMEC grown on polycarbonate filters form a restrictive monolayer of cells, which exhibit dynamic alterations in response to pharmacological agents, thus demonstrating an in vitro model of the BRB. Future studies with the model may offer insights into the pathogenesis of retinal vascular diseases and allow convenient testing of pharmacological interventions.
Yaccino
J A
JA
Pennsylvania State University, Department of Chemical Engineering, University Park 16802, USA.
Chang
Y S
YS
Hollis
T M
TM
Gardner
T W
TW
Tarbell
J M
JM
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001692:Biological Transport / Q000502:physiology; D001813:Blood-Retinal Barrier / Q000502:physiology; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D002417:Cattle; D002478:Cells, Cultured; D004553:Electric Conductivity; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D008222:Lymphokines / Q000494:pharmacology; D008564:Membrane Potentials / Q000502:physiology; D012171:Retinal Vessels / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; D019830:Adenosine-5'-(N-ethylcarboxamide); D016650:Fluorescein-5-isothiocyanate; D000241:Adenosine