Captopril and vascular endothelial growth factor in a mouse model of retinopathy.
OBJECTIVE
Angiotensin converting enzyme (ACE) inhibition has been shown in animal models of retinopathy and in patients with diabetes to improve retinal neovascularization. The mechanism is not clearly identified, but could potentially be mediated via vascular endothelial growth factor modification. The objective of this study was to determine the effect of captopril, an angiotensin converting enzyme (ACE) inhibitor, on retinal VEGF, VEGF-R1, and VEGF-R2 expression in a mouse model of oxygen induced retinopathy (OIR).


METHODS
A mouse model of OIR was used and retinal tissue was obtained at P7, prior to oxygen exposure, at P12, just after oxygen exposure, and at P17, the time of maximal retinal neovascularization for VEGF, VEGF-R1 and VEGF-R2 assessment. A group of animals were treated with captopril (0.5 mg/kg/d SC from P7 for five days).


RESULTS
Captopril plus OIR treated animals had higher levels of retinal VEGF mRNA and protein at P12 (p < 0.05) and lower levels at P17 (p < 0.05) than OIR animals. VEGF-R1 mRNA expression increased 16 fold from P7 to P17 (p < 0.05) in room air reared animals. VEGF-R1 mRNA expression was unaffected by OIR and/or captopril treatment. VEGF-R2 mRNA expression decreased from P7 to P17 by 1.5-fold in room air reared animals (p = 0.001). Retinal VEGF-R2 mRNA and protein expression were significantly higher at P12 in OIR plus captopril treated animals than OIR animals (p = 0.01).


CONCLUSIONS
In summary, captopril maintains VEGF and increases VEGF-R2 expression during the period of hyperoxia when VEGF expression is normally suppressed. Captopril treatment during oxygen exposure is associated with a reduction in the angiogenic response at day 17 as manifested by decreased VEGF and VEGF-R2 expression in retinal tissue. Angiotensin converting enzyme inhibition is associated with changes in expression of VEGF and VEGF-R2 in the evolution of retinal neovascularization in the mouse model of retinopathy.
Higgins
Rosemary D
RD
Department of Pediatrics, Division of Neonatology, Georgetown University Children's Medical Center, Washington, DC, USA. higginsr@mail.nih.gov
Yan
Yun
Y
Geng
Yixun
Y
Sharma
Jotishna
J
Barr
Sybil M
SM
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002216:Captopril / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D018496:Hyperoxia / Q000150:complications; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000378:metabolism; D015861:Retinal Neovascularization / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics* / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics* / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D002216:Captopril; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2