Abstract
Plasma levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and oxidized low density lipoprotein (oxLDL) have been identified as risk factors for cardiovascular disease. Lp-PLA2 is the sole enzyme responsible for the hydrolysis of oxidized phospholipids on LDL particles in atherosclerotic plaques. We have studied the relationship between Lp-PLA2 and oxLDL in carotid endarterectomy (CEA) tissues and in matched plasmas. In extracts from CEA anatomical segments, the levels of oxLDL were significantly associated with the levels of Lp-PLA 2 protein (r = 0.497) and activity (r = 0.615). OxLDL and Lp-PLA2 mass/activity were most abundant in the carotid bifurcation and internal segments where plaque was most abundant. In extracts from CEA atheroma, the levels of oxLDL and Lp-PLA2 were significantly correlated (r = 0.634). In matched plasma and atheroma extracts, the levels of Lp-PLA2 were negatively correlated (r = -0.578). The ratio of Lp-PLA2 to oxLDL was higher in atheromatous tissue (277:1) than in normal tissue (135:1) and plasma (13:1). Immunohistochemical experiments indicated that in plaques, oxLDL and Lp-PLA2 existed in overlapping but distinctly different distribution. Fluorescence microscopy showed both oxLDL and Lp-PLA 2 epitopes on the same LDL particle in plasma but not in plaque. These results suggest that the relationship between Lp-PLA 2 and oxLDL in the atherosclerotic plaque is different from that in the plasma compartment.
Original language | English (US) |
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Pages (from-to) | 1735-1743 |
Number of pages | 9 |
Journal | Journal of lipid research |
Volume | 50 |
Issue number | 9 |
DOIs | |
State | Published - 2009 |
Keywords
- Atherosclerotic plaque
- Carotid endarterectomy
- Lysophosphatidylcholine
- Risk factors
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Endocrinology