VOL. 2, No. 4, October 2005

M. Kawamura, et al. [2005] Med Hypotheses Res 2: 533-541.

Development of Rapid Measurement of Oxidation of
Low-Density Lipoprotein and its Application in Diabetic

Mitsunobu Kawamura*, Keiko Ashidate, Hisako Tohda, Sigeru
Miyazaki, Tamio Teramoto and Yukio Hirata

Abstract. We have developed a new procedure for the rapid measurement of the
oxidation of low-density lipoprotein (LDL) using 2,2’-azobis-4-methoxy-2,4-
dimethylvaleronitorile (V-70) and compared the formation of conjugated diene (CD)
mediated by V-70 with that by Cu2+. The LDL for the V-70-mediated oxidation procedure
was isolated from fresh plasma by vertical centrifugation and immediately used, while that
for the Cu2+–mediated oxidation procedure was obtained after extensive (20 hours) dialysis.
The lag times did not differ significantly (P < 0.02) between the two procedures, both of
which enabled efficient determination of the inhibitory effect of antioxidants on LDL
oxidation. Using the V-70-mediated LDL oxidation procedure, the present study showed that
the lag time in Type 2 diabetic patients was significantly shorter than control subjects,
whereas correlated with fasting plasma glucose and HbA1c levels. Thus, the V-70-mediated
LDL oxidation procedure appeared to be simple, rapid, and clinically applicable for
measuring the susceptibility of LDL to oxidation.

*Address all correspondence to: Dr. Mitsunobu Kawamura, Division of
Endocrinology and Metabolism, Department of Medicine, Tokyo Teishin Hospital, 2-14-23
Fujimi, Chiyoda-Ku, Tokyo, 102-8798, Japan. Phone: 3-5214-7201. Fax: 3-5214-7384.

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