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BioMed Research International
Volume 2015, Article ID 687386, 11 pages
http://dx.doi.org/10.1155/2015/687386
Research Article

Zeaxanthin Inhibits Hypoxia-Induced VEGF Secretion by RPE Cells through Decreased Protein Levels of Hypoxia-Inducible Factors-1α

1Department of Ophthalmology, The New York Eye and Ear Infirmary of Mount Sinai Health System, 310 E. 14th Street, New York, NY 10003, USA
2Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
3Tissue Culture Center, The New York Eye and Ear Infirmary of Mount Sinai Health System, 310 E. 14th Street, New York, NY 10003, USA
4Department of Pathology, The New York Eye and Ear Infirmary of Mount Sinai Health System, 310 E. 14th Street, New York, NY 10003, USA

Received 3 September 2014; Accepted 15 December 2014

Academic Editor: Takashi Saku

Copyright © 2015 Richard Rosen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hypoxia is the most important stimulus leading to upregulation of VEGF in the retina and this is caused by accumulation of hypoxia-inducible factors-1α (HIF-1α) protein. The effects of zeaxanthin, a natural phytochemical, on the VEGF and HIF-1α expression in the primary culture of human retinal pigment epithelial (RPE) cells were studied. An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2) to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without zeaxanthin under normoxic and hypoxic conditions. VEGF and HIF-1α protein and RNA levels were measured by ELISA kits and RT-PCR, respectively. Hypoxia caused a significant increase of VEGF expression and accumulation of HIF-1α in RPE cells. Zeaxanthin at 50–150 μM significantly inhibited the expression of VEGF and accumulation of HIF-1α protein caused by hypoxia but did not affect expression of VEGF and HIF-1α under normoxic conditions. This is the first report on the effect of zeaxanthin on VEGF and HIF-1α levels in cultured RPE cells and suggests that zeaxanthin may have potential value in the prevention and treatment of various retinal diseases associated with vascular leakage and neovascularization.