%0 Journal Article
%A Wang, Lan
%A Li, Chuan-Ming
%A Rudolf, Martin
%A Belyaeva, Olga V.
%A Chung, Byung Hong
%A Messinger, Jeffrey D.
%A Kedishvili, Natalia Y.
%A Curcio, Christine A.
%T Lipoprotein Particles of Intraocular Origin in Human Bruch Membrane: An Unusual Lipid Profile
%B Investigative Ophthalmology & Visual Science
%D 2009
%R 10.1167/iovs.08-2376
%J Investigative Ophthalmology & Visual Science
%V 50
%N 2
%P 870-877
%@ 1552-5783
%X   purpose. Throughout adulthood, Bruch membrane (BrM) accumulates esterified cholesterol (EC) associated with abundant 60- to 80-nm-diameter lipoprotein-like particles (LLP), putative apolipoprotein B (apoB) lipoproteins secreted by the retinal pigment epithelium (RPE). In the present study, neutral lipid, phospholipids, and retinoid components of human BrM-LLP were assayed.  methods. Particles isolated from paired choroids of human donors were subjected to comprehensive lipid profiling (preparative liquid chromatography [LC] gas chromatography [GC]), thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), Western blot analysis, and negative stain electron microscopy. Results were compared to plasma lipoproteins isolated from normolipemic volunteers and to conditioned medium from RPE-J cells supplemented with palmitate to induce particle synthesis and secretion.  results. EC was the largest component (32.4 ± 7.9 mol%) of BrM-LLP lipids. EC was 11.3-fold more abundant than triglyceride (TG), unlike large apoB lipoproteins in plasma. Of the fatty acids (FA) esterified to cholesterol, linoleate (18:2n6) was the most abundant (41.7 ± 4.7 mol%). Retinyl ester (RE) was detectable at picomolar levels in BrM-LLP. Notably scarce in any BrM-LLP lipid class was the photoreceptor-abundant FA docosahexaenoate (DHA, 22:6n3). RPE-J cells synthesized apoB and numerous EC-rich spherical particles.  conclusions. BrM-LLP composition resembles plasma LDL more than it does photoreceptors. An EC-rich core is possible for newly synthesized lipoproteins as well as those processed in plasma. Abundant EC could contribute to a transport barrier in aging and lesion formation in age-related maculopathy (ARM). Analysis of BrM-LLP composition has revealed new aspects of retinal cholesterol and retinoid homeostasis. 
%[ 3/6/2021
%U https://doi.org/10.1167/iovs.08-2376