Comparison of ultracentrifugation and nuclear magnetic resonance spectroscopy in the quantification of triglyceride-rich lipoproteins after an oral fat load.
BACKGROUND
The measurement of triglyceride (TG)-rich particles after an oral fat challenge has been used to provide a measure of risk for coronary artery disease independent of the fasting plasma triglyceride concentration. The analytical "gold standard" for measuring TG-rich lipoproteins uses density gradient ultracentrifugation; however, this technique is labor-intensive. Because of our need to perform numerous postprandial analyses of TG-rich lipoproteins for a large interventional study (Genetics of Lipid Lowering Drugs and Diet Network), we evaluated the use of nuclear magnetic resonance (NMR) spectroscopy for measuring TG-rich particles.


METHODS
EDTA-blood samples were obtained 0, 3.5, 6, and 8 h after ingestion of an oral fat meal (89% of calories from fat) in 20 apparently healthy individuals. The plasma TG concentrations of chylomicron and chylomicron remnant/VLDL fractions were analyzed by ultracentrifugation and NMR spectroscopy.


RESULTS
Comparison of all values (n = 78) by ultracentrifugation (x) and NMR (y) produced a linear regression equation of y = 0.979x - 0.035 mmol/L (R(2) = 0.90) for chylomicrons and y = 1.398x + 0.067 mmol/L (R(2) = 0.96) for the fraction containing chylomicron remnants and VLDL. Postprandial response of chylomicrons and chylomicron remnant/VLDL was similar, with maximum response occurring between 3.5 to 6 h regardless of method of measurement.


CONCLUSIONS
Chylomicron and chylomicron remnant/VLDL fraction measurements obtained by NMR have a high degree of correlation with results produced by ultracentrifugation. NMR may therefore be suitable as an alternative method for the measurement of postprandial TG-rich lipoproteins in individuals consuming a high-fat meal.
Tsai
Michael Y
MY
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA. tsaix001@tc.umn.edu
Georgopoulos
Angeliki
A
Otvos
James D
JD
Ordovas
Jose M
JM
Hanson
Naomi Q
NQ
Peacock
James M
JM
Arnett
Donna K
DK
D000328:Adult; D000368:Aged; D053298:Chylomicron Remnants; D002914:Chylomicrons / Q000097:blood*; D004041:Dietary Fats; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood*; D014461:Ultracentrifugation
D053298:Chylomicron Remnants; D002914:Chylomicrons; D004041:Dietary Fats; D008077:Lipoproteins, LDL; D014280:Triglycerides