Cigarette smoke increases cholesterol oxidation and lipid peroxidation of human low-density lipoprotein and decreases its binding to the hepatic receptor in vitro.
Low-density lipoprotein (LDL) was exposed to six puffs of cigarette smoke (CS) filtered through a glass wool filter and then incubated for 6 or 20 h at 37 degrees C. Control LDL was similarly treated but exposed to air. In cigarette smoke-treated LDL (CS-LDL), compositional changes of the lipid fraction were most detectable after 20 h incubation. These changes included a decrease of polyunsaturated fatty acids (PUFA), slight degradation of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) to their lysophospholipid lysoPE and lyso-PC, elevation of oxidized cholesterol content as well as thiobarbituric acid reacting substance (TBARS), indicating an oxidative effect of CS on LDL. CS-LDL also showed higher anodic electrophoretic mobility and crosslinking of its apoprotein by nondisulfide bonds. The binding affinity of CS-LDL to liver membrane receptor was much lower than control LDL as measured by the calcium-dependent binding of LDL-gold conjugate to the solubilized membrane protein dot blotted onto nitrocellulose strips. Our results indicate that CS induces changes in LDL, making it more atherogenic and cytotoxic.
Mahfouz
M M
MM
Burnsides Research Laboratory, University of Illinois, Urbana 61801, USA.
Hulea
S A
SA
Kummerow
F A
FA
D001055:Apolipoproteins B / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D011973:Receptors, LDL / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism*
D001055:Apolipoproteins B; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D002784:Cholesterol