Accumulation of unesterified cholesterol in limbal cornea and conjunctiva of rabbits fed a high-cholesterol diet. Detection with filipin.

Progressive cholesterol deposition frequently occurs in the corneas, tendons, and arteries of those individuals who have hypercholesterolemia. Many investigators have noted histochemical and chemical similarities in the nature of the lipid that accumulates in these tissues. Lipid-soluble dyes have been used to stain hydrophobic lipids such as cholesteryl ester and triglyceride in previous studies of corneal lipid deposits. In this report, deposits of unesterified cholesterol have been detected in the limbal cornea and conjunctiva of hypercholesterolemic rabbits using the fluorescent dye filipin. Whereas, oil red O-stained lipid accumulated both intra- and extracellularly, unesterified cholesterol accumulated extracellularly, similar to its predominant location in tendon xanthoma and atherosclerotic lesions. The source and mechanism by which unesterified cholesterol accumulates in limbal cornea and conjunctiva, tendons, and arteries remains to be determined.