Breakdown of outer blood retinal barrier (BRB) due to the disruption of tight junctions (TJs) is one of themain factors accounting for diabetic macular edema (DME), a major complication of diabetic retinopathy.Previously it has been shown that PACAP and VIP are protective against several types of retinal injuries.However, their involvement in the maintenance of outer BRB function during DME remains uncovered.Here, using an in vitro model of DME, we explored the effects of both PACAP and VIP. Human retinalpigment epithelial cells (ARPE19) were cultured for 26 days either in normal glucose (5.5 mM, NG) orin high glucose (25 mM, HG). In addition, to mimic the inflammatory aspect of the diabetic milieu, cellswere also treated with IL-1 (NG + IL-1 and HG + IL-1). Effects of PACAP or VIP on cells permeabilitywere evaluated by measuring both apical-to-basolateral movements of fluorescein isothyocyanate (FITC)dextran and transepithelial electrical resistance (TEER). Expression of TJ-related proteins was evaluatedby immunoblot. Results demonstrated that NG + IL-1 and, to a greater extent, HG + IL-1 significantlyincreased FITC-dextran diffusion, paralleled by decreased TEER. PACAP or VIP reversed both of theseeffects. Furthermore, HG + IL-1-induced reduction of claudin-1 and ZO-1 expression was reversed byPACAP and VIP. Occludin expression was not affected in any of the conditions tested. Altogether, thesefinding show that both peptides counteract HG + IL-1-induced damage in ARPE19 cells, suggesting thatthey might be relevant to the maintenance of outer BRB function in DME.

Ameliorative effect of PACAP and VIP against increased permeability in a model of outer blood retinal barrier dysfunction

D'AMICO, AGATA GRAZIA;IMBESI, Rosa;D'AGATA, VELIA MARIA
2013

Abstract

Breakdown of outer blood retinal barrier (BRB) due to the disruption of tight junctions (TJs) is one of themain factors accounting for diabetic macular edema (DME), a major complication of diabetic retinopathy.Previously it has been shown that PACAP and VIP are protective against several types of retinal injuries.However, their involvement in the maintenance of outer BRB function during DME remains uncovered.Here, using an in vitro model of DME, we explored the effects of both PACAP and VIP. Human retinalpigment epithelial cells (ARPE19) were cultured for 26 days either in normal glucose (5.5 mM, NG) orin high glucose (25 mM, HG). In addition, to mimic the inflammatory aspect of the diabetic milieu, cellswere also treated with IL-1 (NG + IL-1 and HG + IL-1). Effects of PACAP or VIP on cells permeabilitywere evaluated by measuring both apical-to-basolateral movements of fluorescein isothyocyanate (FITC)dextran and transepithelial electrical resistance (TEER). Expression of TJ-related proteins was evaluatedby immunoblot. Results demonstrated that NG + IL-1 and, to a greater extent, HG + IL-1 significantlyincreased FITC-dextran diffusion, paralleled by decreased TEER. PACAP or VIP reversed both of theseeffects. Furthermore, HG + IL-1-induced reduction of claudin-1 and ZO-1 expression was reversed byPACAP and VIP. Occludin expression was not affected in any of the conditions tested. Altogether, thesefinding show that both peptides counteract HG + IL-1-induced damage in ARPE19 cells, suggesting thatthey might be relevant to the maintenance of outer BRB function in DME.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/14017
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