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Updated: May 11, 2026

Extracellular Vesicle Tissue Factor Activity Assay
Published on: December 29, 2023
Platelet-activating factor acetylhydrolase is mainly associated with electronegative low-density lipoprotein
Sonia Benítez1, José Luis Sánchez-Quesada, Vicent Ribas
1Servei de Bioquímica and Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Background:
Electronegative LDL [LDL(-)], a modified subfraction of LDL present in plasma, induces the release of interleukin-8 and monocyte chemotactic protein-1 from cultured endothelial cells.
Methods And Results:
We demonstrate that platelet-activating factor acetylhydrolase (PAF-AH) is mainly associated with LDL(-). LDL(-) had 5-fold higher PAF-AH activity than the nonelectronegative LDL subfraction [LDL(+)] in both normolipemic and familial hypercholesterolemic subjects. Western blot analysis after SDS-PAGE confirmed these results, because a single band of 44 kDa corresponding to PAF-AH appeared in LDL(-) but not in LDL(+). Nondenaturing polyacrylamide gradient gel electrophoresis demonstrated that PAF-AH was bound to LDL(-) regardless of LDL size. In accordance with the above findings, nonesterified fatty acids, a cleavage product of PAF-AH, were increased in LDL(-) compared with LDL(+).
Conclusions:
The high PAF-AH activity observed in LDL(-) could be related to the proinflammatory activity of these lipoproteins toward cultured endothelial cells.
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