N-(4-hydroxyphenyl) retinamide augments laser-induced choroidal neovascularization in mice.
OBJECTIVE
To evaluate the effect of N-4-hydroxyphenyl retinamide (4-HPR) on experimental laser-induced choroidal neovascularization (CNV) and on the expression and secretion of relevant growth factors by cultured human retinal pigment epithelial (RPE) cells.


METHODS
CNV was induced by laser photocoagulation in C57BL/6 mice. 4-HPR (0.2 or 1 mg) or vehicle, was injected intraperitoneally twice daily for 14 days. Plasma and tissue levels of 4-HPR were measured by HPLC. CNV was evaluated by fluorescein angiography, histology, and quantitative confocal analysis of isolectin B4 histochemistry on days 7 and 14. Induction of apoptosis and expression and secretion of growth factors was studied in 4-HPR-treated RPE cultures.


RESULTS
Mice treated with 4-HPR exhibited time- and dose-dependent increases in plasma and tissue 4-HPR levels. CNV lesions showed increased volume with increased vascular leakage and contained fewer lesion-associated RPE in treated versus untreated mice. Treatment of nonpolarized RPE cultures with 4-HPR in the presence of serum resulted in RPE apoptosis; however, apoptosis was minimal in similarly treated highly polarized RPE. Treatment of RPE cells with 4-HPR resulted in the upregulation of VEGF-A and -C (P < 0.05) and Ang-1 (P < 0.01) mRNA and increased secretion of VEGF-A and -C (P < 0.05), whereas pigment epithelium-derived growth factor (PEDF) and thrombospondin (TSP)-1 mRNA expression and secretion were downregulated (P < 0.05).


CONCLUSIONS
4-HPR increases lesion size and leakage in laser-induced CNV and is associated with the upregulation of key proangiogenic factors and the downregulation of antiangiogenic factors. Consistent with the preferential loss of RPE in CNV lesions in vivo, 4-HPR induces apoptosis of nonpolarized RPE in the presence of serum.
Sreekumar
Parameswaran G
PG
The Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Childrens Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Zhou
Jiehao
J
Sohn
Joonhong
J
Spee
Christine
C
Ryan
Stephen J
SJ
Maurer
Barry J
BJ
Kannan
Ram
R
Hinton
David R
DR
D043925:Angiogenesis Inducing Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D042683:Angiopoietin-1 / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D002829:Choroid / Q000187:drug effects* / Q000473:pathology; D020256:Choroidal Neovascularization / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D017313:Fenretinide / Q000493:pharmacokinetics / Q000494:pharmacology*; D005451:Fluorescein Angiography; D020287:In Situ Nick-End Labeling; D007274:Injections, Intraperitoneal; D017075:Laser Coagulation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D015843:Serpins / Q000235:genetics / Q000378:metabolism; D019700:Thrombospondin 1 / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D042582:Vascular Endothelial Growth Factor C / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
D043925:Angiogenesis Inducing Agents; D042683:Angiopoietin-1; D005136:Eye Proteins; D017313:Fenretinide; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D015843:Serpins; D019700:Thrombospondin 1; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; D000099174:Pigment Epithelium-Derived Factor; C467628:Angpt1 protein, mouse; C467480:vascular endothelial growth factor A, mouse; C467483:vascular endothelial growth factor C, mouse