Abstract 15590: Is S-Glutathionylated Apoprotein B100 a Potential Marker for Atherogenic Risk?
Background: Oxidative stress is a key factor involved in atherogenesis that induces the reversible formation of mixed disulfides between protein sulfhydryl groups and glutathione (S-glutathionylation) on many proteins, which subsequently alters their functions. Although glutathionylated proteins can be detected by several means, a method of evaluation in vivo has not been established and the physiological function(s) of these proteins remains unclear. Low-density lipoprotein (LDL) cholesterol, especially when modified by oxidative stress, is involved in atherogenic processes. Here, we designed a new protocol to detect the S-glutathionylation of apoprotein B100 (apoB100), a major component of LDL-cholesterol, and evaluated its clinical significance in patients at risk for atherogenesis.
Methods and results: We raised an antibody against a specific glutathionylated domain of the apoB100 peptide (VPSCKLDFRE) and determined its specificity for apoB and for S-glutathionylation by immunoprecipitation and by immunoblotting (with or without dithiothreitol, DTT), respectively. We also confirmed ex vivo that this antibody reflects reversible oxidative status by adding buthionine sulfoximine or DTT to human serum, and quantified S-glutathionylated apoB100 by immunoblotting against the antibody. Preliminary results indicated higher serum levels in patients with carotid artery sclerosis or arteriosclerosis obliterans than controls. We investigated the relationship between levels of S-glutathionylated apoB100, atherogenic risks including LDL subfractions separated by electronegativity (LDL-1, -2 and -3) and high-sensitive CRP (hs-CRP) in 120 patients (age 65.2 years, 69 males) at high risk for atherogenesis due to hypertension, dyslipidemia and/or diabetes mellitus. S-glutathionylated apoB100 correlated significantly and negatively with LDL-1 (r = −0.299, p = 0.001), and positively with LDL-2 and -3, the most negatively charged fraction, (r = 0.290 and r = 0.299, respectively both p = 0.001), but not with hsCRP, HbA1c and blood pressure.
Conclusion: S-glutathionylated apoB100 might reflect reversible oxidative status and thus serve as a potential atherogenic risk factor.
- © 2010 by American Heart Association, Inc.