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Abstract
PURPOSE: To understand the difference between macular and peripheral regions, tissue samples of human retina, retinal pigment epithelium, and Bruch's membrane/choroid were dissected and analyzed for lipid composition. METHOD: To facilitate dissections and enhance the recovery of tissues, eyecups were prefixed for 1 hour in 10% formalin (pH 7). Lipids were extracted from 4-mm trephined punches of tissues and analyzed by high-performance liquid chromatography. After separation of neutral lipids and phospholipids, total fatty acids in both lipid classes were quantitated. RESULTS: The major phospholipid classes in retina, retinal pigment epithelium, and Bruch's membrane/choroid were phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, and phosphatidyl serine; the major fatty acids were palmitic (16:0), stearic (18:0), and oleic (18:1). Although the three tissues had similar total fatty acid and phospholipid components, their relative compositions were different. Neutral lipid/phospholipid ratios in retinal pigment epithelium and Bruch's membrane/choroid were almost three times higher than in the retina. CONCLUSIONS: This study provides information about the lipid composition of macular and peripheral regions of the human retina, retinal pigment epithelium, and Bruch's membrane/choroid. The methodology employed enabled study of lipids in small amounts of tissue, which will be of value in investigating the biochemical aspects of age-related macular degeneration.