Attenuation of choroidal neovascularization by β(2)-adrenoreceptor antagonism.

OBJECTIVES

To determine whether β-adrenergic blockade inhibits choroidal neovascularization (CNV) in a mouse model of laser-induced CNV and to investigate the mechanism by which β-adrenoreceptor antagonism blunts CNV.

DESIGN

Mice were subjected to laser burns, inducing CNV, and were treated with daily intraperitoneal injections of propranolol hydrochloride. Neovascularization was measured on choroidal-scleral flat mounts using intercellular adhesion molecule 2 immunofluorescence staining. The effect of β-adrenoreceptor signaling on expression of vascular endothelial growth factor (VEGF) was investigated using primary mouse choroidal endothelial cells (ChECs) and retinal pigment epithelial (RPE) cells. These cells were incubated with β-adrenoreceptor agonists and/or antagonists and assayed for Vegf messenger RNA and protein levels.

SETTING

University of Wisconsin School of Medicine and Public Health.

PARTICIPANTS

Wild-type 6-week-old female C57BL/6j mice.

MAIN OUTCOME MEASURES: Inhibition of CNV after propranolol treatment and Vegf messenger RNA and protein expression after treatment with β-adrenoreceptor agonists and antagonists.

RESULTS

Propranolol-treated mice demonstrated a 50% reduction in laser-induced CNV. Treatment with norepinephrine bitartrate stimulated Vegf messenger RNA expression and protein secretion in ChECs and RPE cells. This effect was blocked by β2-adrenoreceptor antagonism and mimicked by β2-adrenoreceptor agonists.

CONCLUSIONS

Attenuation of CNV is achieved by β-adrenergic blockade. The β2-adrenoreceptors regulate VEGF expression in ChECs and RPE cells.

CLINICAL RELEVANCE: Antagonists of β-adrenoreceptors are safe and well tolerated in patients with glaucoma and cardiovascular disease. Thus, blockade of β-adrenoreceptors may provide a new avenue to inhibit VEGF expression in CNV.