title: Vitamin E/lipid peroxide ratio and susceptibility of LDL to oxidative modification in non-insulin-dependent diabetes mellitus.
abstract: The presence of conventional risk factors cannot sufficiently account for the excess risk of atherosclerosis in patients with non-insulin-dependent diabetes mellitus (NIDDM). Oxidative modification of LDL has been implicated in the pathogenesis of coronary atherosclerosis. Thirty-five patients with NIDDM, 20 nondiabetic, hypertriglyceridemic subjects (HTG-control), and 21 diabetic, normotriglyceridemic subjects (NTG-control) were enrolled in this study. Oxidative susceptibility of LDL was determined by monitoring formation of conjugated dienes. Mean lag time of LDL oxidation and vitamin E/lipid peroxide of LDL was lower in patients with NIDDM (43.2 +/- 3.9 minutes and 1.6 +/- 1.3) than in HTG-control (48.8 +/- 3.2 minutes and 2.3 +/- 1.2, respectively) and NTG-control subjects (54.2 +/- 6.1 minutes and 3.0 +/- 1.8, respectively). Mean LDL particle size in patients with NIDDM and HTG-control subjects (24.4 +/- 0.9 and 24.7 +/- 0.7 nm, respectively) was smaller than in NTG-control subjects (25.9 +/- 1.0 nm). Multiple stepwise regression analyses ascertained that the vitamin. E/lipid peroxide of LDL is a major determinant of LDL oxidation lag time. These results suggest that LDL in patients with NIDDM is more susceptible to oxidative modification primarily because of a reduced level of vitamin E/lipid peroxide of LDL. The enhanced susceptibility of LDL to oxidation may be a pivotal factor underlying the increased incidence of vascular disease in patients with NIDDM.
authors.affiliation: First Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D008078:Cholesterol, LDL / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008054:Lipid Peroxides / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010084:Oxidation-Reduction; D017698:Postmenopause; D012044:Regression Analysis; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism*
chemical_list: D008078:Cholesterol, LDL; D008054:Lipid Peroxides; D008077:Lipoproteins, LDL; D014280:Triglycerides; C099252:oxidized low density lipoprotein; D014810:Vitamin E