Oxidized low-density lipoprotein reduces plasma coagulation in vitro

Area of Science:

• Biochemistry
• Cardiovascular Science
• Hematology

Background:

• Oxidation of low-density lipoprotein (LDL) involves lipid peroxidation and apolipoprotein modification in vivo.
• Oxidized LDL (Ox-LDL) is implicated in various pathological processes.

Purpose of the Study:

• To investigate the impact of Ox-LDL on plasma coagulation.
• To identify the specific component of Ox-LDL responsible for coagulation alterations.

Main Methods:

• Measurement of prothrombin time (PT) and partial thromboplastin time (PTT) after adding Ox-LDL to normal plasma.
• Lipoprotein delipidation and chemical modification of LDL apolipoprotein.
• Quantification of plasma ionized calcium levels.

Main Results:

• Ox-LDL, but not native LDL, dose- and time-dependently prolonged PT and PTT by 30%.
• The pro-coagulant effect persisted after delipidation, implicating the apolipoprotein fraction.
• Ox-LDL reduced plasma ionized calcium by 33%, and calcium supplementation reversed the coagulation effect.

Conclusions:

• Oxidized LDL apolipoprotein, not its lipid fraction, influences plasma coagulation.
• Ox-LDL may affect coagulation by binding calcium ions, thereby reducing plasma ionized calcium levels.