Composition and ultrastructure of size subclasses of normal human peripheral lymph lipoproteins: quantification of cholesterol uptake by HDL in tissue fluids

Citation
Mn. Nanjee et al., Composition and ultrastructure of size subclasses of normal human peripheral lymph lipoproteins: quantification of cholesterol uptake by HDL in tissue fluids, J LIPID RES, 42(4), 2001, pp. 639-648
Citations number
51
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF LIPID RESEARCH
ISSN journal
0022-2275 → ACNP
Volume
42
Issue
4
Year of publication
2001
Pages
639 - 648
Database
ISI
SICI code
0022-2275(200104)42:4<639:CAUOSS>2.0.ZU;2-4
Abstract
Peripheral lymph lipoproteins have been characterized in animals, but there is little information about their composition, and none about their ultras tructure, in normal humans. Therefore, we collected afferent leg lymph from 16 healthy males and quantified lipids and apolipoproteins in fractions se parated by high performance-size exclusion chromatography. Apolipoprotein B (apoB) was found almost exclusively in low density lipoproteins. The distr ibution of apoA-I, particularly in lipoprotein A-I (LpA-I) without A-II par ticles, was shifted toward larger particles relative to plasma. The fractio ns containing these particles were also enriched in apoA-II, apoE, total ch olesterol, and phospholipids and had greater unesterified cholesterol-to-ch olesteryl ester ratios than their counterparts in plasma. Fractions contain ing smaller apoA-I particles were enriched in phospholipid, Most apoA-IV wa s lipid poor or lipid free. Most apoC-III coeluted with large apoA-I-contai ning particles. Electron microscopy showed that lymph contained discoidal p articles not seen in plasma. These findings support other evidence that hig h density lipoproteins (HDL) undergo extensive remodeling in human tissue f luid. Total cholesterol concentration in lymph HDL was 30% greater (P < 0.0 5) than could be explained by the transendothelial transfer of HDL from pla sma, providing direct confirmation that HDL acquire cholesterol in the extr avascular compartment. Net transport rates of new HDL cholesterol in the ca nnulated vessels corresponded to a mean whole body reverse cholesterol tran sport rate via lymph of 0.89 mmol (344 mg)/day.