Properties of low density lipoproteins relevant to oxidative modifications change paradoxically during aging.
Atherosclerosis is a common problem among the elderly. Because lipid peroxidation is considered a contributor to the development of atherosclerosis, we compared oxidative properties of lipoproteins in an otherwise healthy (SENIEUR-classified) aged population (65-74 years) with young controls (18-30 years). Relative amounts of oxidatively altered low density lipoprotein (LDL), estimated by means of an antibody against LDL modified by 4-hydroxynonenal, a product of lipid peroxidation, were increased marginally in serum from the elderly (9.8 vs. 7.4%, P = 0.07). In contrast, isolated LDL from the elderly revealed a decreased susceptibility to in vitro oxidation: the lag time was increased (2.34 vs. 2.10 h, P < 0.01), and the maximal rate of LDL oxidation decreased (0.88 vs. 1.01 O.D./h, P = 0.001). However, there were no age-related changes in lipid composition of native LDL and consumption of fatty acids during in vitro oxidation. The serum concentrations of ascorbic acid and most lipophilic anti-oxidants (the latter expressed per g serum lipids) were significantly decreased in the elderly except tocopherols which tended to be higher. In conclusion, our data reveal paradox age-related alterations of LDL as to its behaviour in oxidation in vivo vs. in vitro.
Stulnig
T M
TM
Institute for General and Experimental Pathology, University of Innsbruck, Austria.
Jürgens
G
G
Chen
Q
Q
Moll
D
D
Schönitzer
D
D
Jarosch
E
E
Wick
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000447:Aldehydes / Q000097:blood; D000975:Antioxidants / Q000032:analysis; D001161:Arteriosclerosis / Q000378:metabolism*; D001205:Ascorbic Acid / Q000097:blood; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000097:blood / Q000737:chemistry*; D008297:Male; D010084:Oxidation-Reduction; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014815:Vitamins / Q000097:blood
D000447:Aldehydes; D000975:Antioxidants; D005227:Fatty Acids; D008077:Lipoproteins, LDL; D017392:Thiobarbituric Acid Reactive Substances; D014815:Vitamins; C099252:oxidized low density lipoprotein; C027576:4-hydroxy-2-nonenal; D001205:Ascorbic Acid