Lipid oxidation in unfractionated serum and plasma

Area of Science:

• Biochemistry
• Analytical Chemistry
• Clinical Chemistry

Background:

• Plasma lipid oxidation is a critical factor in various diseases.
• Developing a reliable assay for lipid oxidation susceptibility is essential for clinical diagnostics.
• Previous methods for assessing lipid oxidation have limitations.

Purpose of the Study:

• To develop and validate a spectroscopic assay for measuring plasma lipid susceptibility to oxidation.
• To investigate the complex kinetics of copper-induced lipid oxidation in plasma and serum.
• To understand the influence of various factors, including anticoagulants, ions, and antioxidants, on oxidation kinetics.

Main Methods:

• Studied copper-induced oxidation kinetics in diluted human serum and plasma using spectrophotometry.
• Varied anticoagulant types (heparin, citrate, EDTA), ion concentrations (citrate, chloride), copper concentrations, and the presence of ascorbic acid.
• Monitored absorbance changes at multiple wavelengths to quantify oxidation products.

Main Results:

• Identified complex interactions between ascorbic acid, citrate, and chloride ions affecting oxidation kinetics.
• Observed that copper-citrate chelate-induced oxidation onset is minimally affected by chloride but accelerated by copper concentration.
• Demonstrated that in the absence of citrate, chloride concentration significantly impacts the lag phase before oxidation, and copper concentration shows a biphasic effect on this lag in PBS.

Conclusions:

• The spectroscopic method, under optimized conditions, correlates with independent measurements of polyunsaturated fatty acid consumption.
• The developed spectroscopic assay shows potential for evaluating plasma lipid oxidation susceptibility.
• Further research is needed to correlate in vitro oxidation susceptibility with clinical factors.