Effects of vitamin E on the toxicity of oxidized LDL on endothelial cells in vitro in smokers vs nonsmokers on diets rich in fish.
OBJECTIVE
To clarify whether supplementation of vitamin E can alter the low density lipoprotein (LDL) oxidation properties and thereby affect endothelial cell function and prostacyclin production in smokers compared to nonsmokers on diets rich in fish in a pilot study.


METHODS
The LDL of six smokers and six nonsmokers on habitual high fish diet was isolated before and after an 8-week supplementation of vitamin E (800 IU/day). LDL was oxidized by incubation with CuSO4. Cytotoxicity of LDL oxidized to different degrees on endothelial cells was investigated in vitro in these two groups.


METHODS
Helsinki University Central Hospital; Institute of Biomedicine, Pharmacology, University of Helsinki.


RESULTS
At baseline, the rate of oxidation was higher in nonsmokers than in smokers. The lag phase increased significantly after the supplementation of vitamin E both in smokers and nonsmokers. Native LDL dose dependently tended to reduce the viability of endothelial cells in vitro more markedly when isolated from smokers than from nonsmokers. Vitamin E supplementation had no beneficial effect on the cytotoxicity of oxidized LDLs in endothelial cell culture. On the other hand, simultaneous administration of Trolox, the water-soluble analogue of vitamin E, attenuated the LDL cytotoxicity on endothelial cells. The vitamin E supplementation to LDL donors attenuated the increase in prostacyclin production both in smokers and nonsmokers.


CONCLUSIONS
Supplementation of LDL donors (healthy male volunteers on habitual fish diet) with vitamin E increased the lag phase of LDL oxidation, but, on the other hand, did not influence in vitro cytotoxicity of LDL, or prostacyclin production.
Seppo
L
L
Institute of Biomedicine, Pharmacology, University of Helsinki, Finland.
Lähteenmäki
T
T
Tikkanen
M J
MJ
Vanhanen
H
H
Korpela
R
R
Vapaatalo
H
H
D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D002478:Cells, Cultured / Q000187:drug effects; D004032:Diet / Q000379:methods*; D019587:Dietary Supplements; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D011464:Epoprostenol / Q000097:blood / Q000378:metabolism; D005395:Fish Oils / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000009:adverse effects / Q000097:blood / Q000378:metabolism* / Q000633:toxicity; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects; D010865:Pilot Projects; D012016:Reference Values; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism*; D014810:Vitamin E / Q000494:pharmacology*
D000975:Antioxidants; D005395:Fish Oils; D008055:Lipids; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D014810:Vitamin E; D011464:Epoprostenol