The EC mass in native RPE ranged from 1.9 to 24.2 μg/mg cell protein, with the proportion of TC that is esterified ranging from 0.09 to 0.40
(Table 3) . Then, by ESI/MS assay, the EC composition in RPE and partially isolated BrM from fresh tissues
(Fig. 7)was similar to that in the isolated BrM/Ch LLP fractions (compare with
Fig. 2 ). That is, cholesteryl linoleate was more than two times more abundant than cholesterol oleate, and little cholesterol docosahexaenoate was detectable. However, a different picture emerged from analysis of EC composition of BrM, cornea, and sclera of paraformaldehyde-preserved eyes. Cornea and sclera, like LDL, are relatively enriched in cholesteryl linoleate, but preserved BrM, like intracellular droplets of activated macrophages, is enriched in cholesteryl oleate
(Fig. 8A) . We also compared the EC composition of preserved BrM to RPE and retina of the same eyes
(Fig. 8C) . All three tissues were enriched in cholesteryl oleate, although the total
mass of cholesteryl oleate differed substantially among them (6700 ± 1156, 1190 ± 850, and 180 ± 67 nanomoles/g dry weight, respectively), consistent with the previously reported measurable but low EC mass in the neurosensory retina.
14 Finally, in fellow eyes in which BrM, retina, sclera, and cornea were preserved for 7 days or processed fresh, all ocular regions of both eyes were cholesteryl linoleate–enriched (not shown). In fellow eyes preserved or frozen for 3 months, tissues from only the frozen eye was cholesterol linoleate–enriched (not shown). These results raise the possibility that BrM EC composition is affected by long-term storage differently than are esters of plasma lipoprotein origin that accumulate in sclera and cornea.