Inhibition of choroidal neovascularization by topical application of angiogenesis inhibitor vasostatin.
OBJECTIVE
Choroidal neovascularization (CNV) is the leading cause of blindness in patients with age-related macular degeneration (AMD). This study evaluated the inhibitory effect of vasostatin (VS), an endogenous angiogenesis inhibitor, on CNV.


METHODS
Anti-angiogenic activity of VS was evaluated in vitro by migration and tube formation assays in human umbilical vein endothelial cells (HUVECs). CNV lesions were induced in Brown Norway rats by fundus argon laser photocoagulation. Beginning one day after CNV induction, rats were treated with eye drops containing 1 microg/ml VS in PBS buffer for three times daily for 20 days. The extent of CNV was examined by flat mount analysis on day 24 or by fundus fluorescein angiography (FAG) on days 21, 28, 35, and 42, respectively. CNV lesions and choroidal vascularity were evaluated by histological analysis. The spatial distribution of topically applied VS in rat eyes was evaluated by immunoblot analysis.


RESULTS
VS inhibited migration and tube formation in HUVECs. Flat mount analysis revealed that, after laser-induced photocoagulation, topical VS application for 20 days significantly reduced CNV lesions. Moreover, serial FAG analysis indicated that a 20 day VS treatment significantly reduced CNV lesions on all subsequent days. Histological analysis revealed attenuated lesions, intact Bruch's membrane, and reduced choroidal vascularity in VS-treated eyes. Finally immunoblot analysis reveled VS expression in choroids.


CONCLUSIONS
Topical VS application suppresses the progression of laser-induced CNV via angiogenesis inhibition and may constitute a therapeutic alternative for excessive neovascularization occurring with ocular diseases.
Sheu
Shwu-Jiuan
SJ
Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
Bee
Youn-Shen
YS
Ma
Yi-Ling
YL
Liu
Guei-Sheung
GS
Lin
Hsiu-Chen
HC
Yeh
Tse-Liang
TL
Liou
Jau-Chen
JC
Tai
Ming-Hong
MH
D000287:Administration, Topical; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D037282:Calreticulin / Q000494:pharmacology*; D002465:Cell Movement / Q000187:drug effects; D020256:Choroidal Neovascularization / Q000517:prevention & control*; D042783:Endothelial Cells / Q000187:drug effects / Q000473:pathology; D005451:Fluorescein Angiography; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D007834:Lasers; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011914:Rats, Inbred BN; D012160:Retina / Q000187:drug effects
D020533:Angiogenesis Inhibitors; D037282:Calreticulin; D010446:Peptide Fragments; C121986:vasostatin