HDL2 can inhibit further oxidative modification of partially oxidized LDL.
OBJECTIVE
To investigate whether HDL(2) can inhibit further oxidative modification of partially oxidized LDL (ox-LDL) by interrupting the chain oxidation reaction after lipid hydroperoxides (LOOH) formation.


METHODS
Following incubation of LDL 400 microg protein/mL phosphate-buffered saline with Cu(2+) for 1.75 h (defined as 0 min), incubation was continued after adding HDL(2) 200 microg protein/mL or HDL(2) 800 microg protein/mL to give both ox-LDL+HDL(2) 200 microg protein/mL or ox-LDL+HDL(2) 800 microg protein/mL. As a control, ox-LDL 200 microg protein/mL and native LDL were prepared. Each sample was subjected to agarose gel electrophoresis and the LOOH in each sample was measured.


RESULTS
When the electrophoretic mobility of native LDL was designated 1, the relative electrophoretic mobility (REM) of ox-LDL increased significantly over time. The REMs of ox-LDL+HDL(2) 800 microg protein/mL from 10 min to 9 h were significantly lower than the REM of ox-LDL at the respective times (p<0.01). LOOH of ox-LDL+HDL(2) 800 microg protein/mL at 1, 3, 6 and 9 h was significantly higher than LOOH in ox-LDL at the respective times (p<0.01). The results of ox-LDL+HDL(2) 200 microg protein/mL were almost the same but to a lesser extent than the results of ox-LDL+HDL(2) 800 microg protein/mL.


CONCLUSIONS
The present findings suggest that HDL(2) can inhibit further oxidative modification of partially oxidized LDL by interrupting the chain oxidation reaction after LOOH formation in a concentration-dependent manner.
Sakuma
Nagahiko
N
Department of Cardio-Renal Medicine and Hypertension, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. sakuma@med.nagoya-cu.ac.jp
Saeki
Tomoaki
T
Ito
Tatsuya
T
Hibino
Takeshi
T
Suzuki
Shogo
S
Kunimatsu
Mitoshi
M
Yamamoto
Koji
K
Kitada
Syuichi
S
D003300:Copper / Q000494:pharmacology; D004587:Electrophoresis, Agar Gel; D006801:Humans; D066298:In Vitro Techniques; D008054:Lipid Peroxides / Q000096:biosynthesis; D053439:Lipoproteins, HDL2 / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism*; D010084:Oxidation-Reduction
D008054:Lipid Peroxides; D053439:Lipoproteins, HDL2; D008077:Lipoproteins, LDL; D003300:Copper