Epinephrine, but not dexamethasone, induces apoptosis in retinal pigment epithelium cells in vitro: possible implications on the pathogenesis of central serous chorioretinopathy

Abstract 

Background: The pathogenesis of central serous chorioretinopathy is poorly understood. It is believed to be due to dysfunction of the retinal pigment epithelium and/or choroid and has been associated with elevated levels of epinephrine and administration of corticosteroids. Epinephrine and corticosteroids have previously been shown to induce apoptosis (programmed cell death) in various types of cells. The objective of this study was to investigate whether these agents can induce apoptosis in cultured retinal pigment epithelium cells. This may help elucidate the pathogenesis of central serous chorioretinopathy.  Methods: Third-passage porcine retinal pigment epithelium cells were grown to confluence and incubated for 1–7 days in culture medium containing epinephrine (10²–10⁹ pg/ml) or a corticosteroid, dexamethasone (4–4×10⁴ ng/ml). The cultures were evaluated for apoptosis by phase-contrast microscopy and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling.  Results: Epinephrine (7×10⁷– 10⁹ pg/ml) induced apoptosis in a dose- and time-dependent manner. Exposure to lower concentrations of epinephrine (10²–6×10⁷ pg/ml) and all tested levels of dexamethasone did not result in apoptosis.  Conclusion: Retinal pigment epithelium cells may undergo apoptosis following exposure to elevated levels of epinephrine. These findings suggest a possible pathophysiologic mechanism for the development of central serous chorioretinopathy.