AUTHORS: J. Brinks¹, E.H.C. van Dijk¹; M. Habeeb¹; A. Nikolaou¹;; R. Tsonaka²; H.A.B. Peters^{3, 5}; H.C.M. Sips⁴; A.F. van de Merbel⁶; E.K. de Jong⁷; R.G.E. Notenboom⁸; S.M. Kielbasa²; S.M. van der Maarel⁹; P.H.A. Quax^{3, 5}; O.C. Meijer⁴; C.J.F. Boon¹

ABSTRACT BODY:

Purpose: Central serous chorioretinopathy is a chorioretinal disease, of which the exact pathogenesis is unknown. The disease originates in the choroid, with secondary dysfunction of the retinal pigment epithelium, resulting in accumulation of subretinal fluid. Exposure to corticosteroids forms the most important risk factor for central serous chorioretinopathy. We developed a cell model to study the role of corticosteroids in central serous chorioretinopathy.

Methods: Choroidal endothelial cells were isolated from cadaveric human donors. Magnetic-activated cell sorting with anti-human CD31 was performed for choroidal endothelial cell isolation. Isolated choroidal endothelial cells formed capillary-like structures in Matrigel and expressed endothelial cell-specific markers. Primary cultures of purified choroidal endothelial cells treated with intermittent administration of 10-7 M cortisol were analysed for the effect on both direct and downstream putative corticosteroid responsive genes (FKBP5, PER1, GILZ1, and SGK1).

Results: We found that intermittent administration of 10-7 M cortisol (mimicking the in vivo situation with diurnal rhythm in blood cortisol levels) led to significant transcriptional upregulation of validated cortisol target genes. Further pharmacological analysis identified the glucocorticoid receptor rather than the mineralocorticoid receptor as the mediator of the cortisol effect on gene expression.

Conclusion: In this study we describe an optimized choroidal endothelial cell isolation and culturing protocol. This ex vivo model appears to be very suitable for studying both central serous chorioretinopathy, and other diseases in which corticosteroids and choroidal endothelial cells are involved.