Fractional and molar esterification rate of high density lipoprotein cholesterol determined by high performance liquid chromatography

Abstract

Objective To develop an HPLC method for the measurement of fractional and molaresterification rate of serum HDL(FER HDL and MERHDL).Methods Blood samples were mixed with 5,5'-dithiobis-(2-nitrobenzoic acid)(DTNB)and the sera were separated.Serum HDL fractions were prepared by precipitation with Dextran sulfate and magnesium and the fractions were incubated at 37℃for 1 h in the presence and absence of 2-mercaptoethanol(ME).Free cholesterol levels of the HDL fractions were analyzed by HPLC and FERHDL and MERHDL were calculated.Results Under the selected conditions,serum free cholesterol could be stabilized by inhibition of LCAT with DTNB and the inhibition be reversed by ME. The total CVs for FERHDL and MERHDL were 1.59%-3.74% and 1.64%-2.88%,respectively.The averages of FERHDL and MERHDL in 70 apparently healthy subjects were 18.7%/h and 42.7 μmol·L-1·h-1 with standard deviations of 7.2%/h and 11.8 μmol·L-1·h-1·respectively,and the medians were 16.1%/h and 11.8 μmol·L-1·h-1.Close correlations of FERHDL.and MERHDL with other cardiovascular disease risk factors were observed.Conclusion A new method for the measurements of FERHDL and MERHDL by HPLC has been estabished. The method is safe, precise and simple and applications in the assessment of cardiovascular diseases risks are expected. Key words: Lipoproteins HDL; Cholesterol; Chromatography, higy pressure liquid