This study was undertaken to investigate the distribution of vitamin E in the macular and peripheral regions of the human retina, retinal pigment epithelium (RPE) and choroid as a function of age. High-performance liquid chromatography (HPLC) was used to measure α and γtocopherol levels quantitatively using tocol as an internal standard. In 57 out of 70 donor eyes (ages 9-104) the macular region was isolated and the tocopherols analyzed. The conventional brush method and a new vortex method were used to isolate the retinal pigment epithelium cells. Similar trends for the vitamin E levels (increase to the 5th decade, decrease after 7th decade) were found for the macular and peripheral retina and for the macular RPE. In the peripheral RPE a slight continuous increase with age was found. The vitamin E levels are higher in the RPE than in the retina, for both macular and peripheral regions. The amounts of vitamin E/mg protein are lower in the macular retina than in the peripheral retina, whereas in the RPE there is no difference in vitamin E content between macular and peripheral regions. A simple method based on a gentle vortex step was found to offer several advantages over the more generally used isolation of RPE cells based on brushing, and there was no difference in recovery of vitamin E in RPE cells when they were isolated by either isolation technique. It was also found that denominators, used to express the values of vitamin E in tissues should, be used with care since age dependent trends in parameters/denominators could be caused by trends in the denominators only.
Bibliographical noteFunding Information:
This work was supported by a grant from the National Eye Institute (EY 088 18). The authors thank the technicians of the Montana Eye Bank for preparation of the donated eye tissues. The authors also thank Hoffmann La-Roche (Nutley, NJ), who kindly provided tocol. We thank Sharon Hapner for her help with the protein assay and we thank Garry J. Handelman for his assistance with the vitamin E assay. The authors also acknowledge Roy C. Milton for assistance with the statistical analysis.
- Age-related macular degeneration (ARMD)
- Retinal pigment epithelium (RPE)
- Vitamin E