Lipoprotein-specific transport of circulating lipid peroxides.
BACKGROUND
Serum lipoproteins, the carriers of cholesterol and other lipophilic substances in blood, are known to contain variable amounts of lipid peroxides. We investigated the transport of food-derived and endogenously formed lipid peroxides by serum lipoproteins under physiological conditions.


METHODS
Five independent trials were conducted in which different groups of healthy volunteers either consumed a test meal (a standard hamburger meal rich in lipid peroxides) or underwent strenuous physical exercise. The transport function was characterized by analyzing the kinetics of lipid peroxides in lipoprotein fractions. For evaluation of their potential involvement, indicators of oxidative stress (8-isoprostanes, malondialdehyde, 8-oxo-deoxyguanosine), antioxidant functions (total antioxidant potential, paraoxonase activity), and serum lipids were also analyzed.


RESULTS
We found that food lipid peroxides are incorporated into serum triglyceride-rich lipoproteins and low-density lipoprotein, directing the flow of lipid peroxides towards peripheral tissues. High-density lipoprotein appears to have an opposite and protective function, and is able to respond to oxidative stress by substantially increasing the reverse transport of lipid peroxides.


CONCLUSIONS
We propose that the specific atherosclerosis-related effects of serum lipoproteins are not explained by cholesterol transport alone and may rather result from the transport of the more directly atherogenic lipid peroxides.
Ahotupa
Markku
M
MCA Research Laboratory, Department of Physiology, University of Turku, Turku, Finland. markku.ahotupa@utu.fi
Suomela
Jukka-Pekka
JP
Vuorimaa
Timo
T
Vasankari
Tommi
T
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D001692:Biological Transport; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D015444:Exercise / Q000502:physiology; D005260:Female; D005502:Food; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology*; D008054:Lipid Peroxides / Q000097:blood* / Q000493:pharmacokinetics*; D008075:Lipoproteins, HDL / Q000097:blood* / Q000502:physiology; D008077:Lipoproteins, LDL / Q000097:blood* / Q000502:physiology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress; D019518:Postprandial Period / Q000502:physiology; D014280:Triglycerides / Q000097:blood* / Q000502:physiology; D055815:Young Adult
D004041:Dietary Fats; D008054:Lipid Peroxides; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D014280:Triglycerides; C075750:8-epi-prostaglandin F2alpha; D008315:Malondialdehyde; D000080242:8-Hydroxy-2'-Deoxyguanosine; D015237:Dinoprost; D003849:Deoxyguanosine