Topical application of recombinant calreticulin peptide, vasostatin 48, alleviates laser-induced choroidal neovascularization in rats.
OBJECTIVE
Vasostatin 48 (VS48) is a peptide of 48 amino acids derived from calreticulin. This study aimed to investigate the effects of topical application of VS48 eyedrops on experimental choroidal neovascularization (CNV).


METHODS
Recombinant VS48 was expressed and purified as a thioredoxin (TRX)-fused protein, TRX-VS48. The anti-angiogenic effects of TRX-VS48 were validated by migration and tube formation assays performed on cultured endothelial cells, and by rat aorta ring assays. CNV lesions were created in Brown Norway rats by laser-induced photocoagulation at day 1. After topical TRX-VS48 application for 21 days, the CNV lesions were monitored via either choroidal flat mounts on day 21 or by fluorescent angiography on days 21, 28, 35, and 42. CNV lesions were evaluated by histological analysis. The retinal function of animals was examined by electroretinogram (ERG) to evaluate the safety and therapeutic efficacy of TRX-VS48.


RESULTS
Application of TRX-VS48 inhibited the migration and tube formation of endothelial cells. TRX-VS48 inhibited the growth of sprouting vessels in aorta rings. ERG analysis revealed that topical TRX-VS48 application for 21 days had no effect on rat retinal functions. After CNV induction, topical TRX-VS48 application for 21 days significantly reduced the size of CNV, as assayed by flat mounts. Fluorescent angiography revealed that the CNV areas in TRX-VS48-treated eyes were significantly reduced compared with TRX-treated eyes on days 21, 28, 35, and 42. Histological analysis also revealed attenuated CNV lesions in TRX-VS48-treated eyes. Topical TRX-VS48 treatment significantly reversed the CNV-induced alterations in ERG parameters on day 35.


CONCLUSIONS
Topical TRX-VS48 application suppressed laser-induced CNV in rats, thereby constituting a possible modality for ocular diseases due to excessive angiogenesis.
Bee
Youn-Shen
YS
Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
Sheu
Shwu-Jiuan
SJ
Ma
Yi-Ling
YL
Lin
Hsiu-Chen
HC
Weng
Wen-Tsang
WT
Kuo
Hsiao-Mei
HM
Hsu
Huei-Chun
HC
Tang
Chia-Hua
CH
Liou
Jau-Cheng
JC
Tai
Ming-Hong
MH
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000473:pathology; D037282:Calreticulin / Q000008:administration & dosage* / Q000009:adverse effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D020256:Choroidal Neovascularization / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D004596:Electroretinography; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D005451:Fluorescein Angiography; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D008297:Male; D009883:Ophthalmic Solutions; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000009:adverse effects; D011832:Radiation Injuries / Q000150:complications*; D051381:Rats; D011914:Rats, Inbred BN; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000009:adverse effects; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000009:adverse effects; D012160:Retina / Q000187:drug effects / Q000503:physiopathology; D015861:Retinal Neovascularization / Q000175:diagnosis; D013879:Thioredoxins / Q000008:administration & dosage / Q000009:adverse effects
D020533:Angiogenesis Inhibitors; D037282:Calreticulin; D009883:Ophthalmic Solutions; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C551388:vasostatin 48; D013879:Thioredoxins
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