RESUMEN
Smoking is a leading cause of atherosclerosis acting trough a wide spectrum of mechanisms, notably the increase of the proatherogenic effect of dyslipidemia. However, a severe atherosclerotic disease is frequently observed in smokers who do not present an overt dyslipidemia. In the present study, we sought to determine if abnormalities in lipid metabolism occur in normolipidemic smokers, focusing especially on the components of intravascular remodeling of high-density lipoprotein (HDL) For this purpose, we measured lipid transfer proteins and enzymes involved in the reverse cholesterol transport (RCT) system in 29 adults: 15 smokers and 14 controls. The blood samples were drawn in the fasting state, immediately after the smokers smoked 1 cigarette. The composition of HDL particles was analyzed after isolation of HDL fractions by microultracentrifugation. We observed that normolipidemic smokers present higher total plasma and HDL phospholipids (PL) (P < .05), 30% lower postheparin hepatic lipase (HL) activity (P < .01), and 40% lower phospholipid transfer protein (PLTP) activity (P < .01), as compared with nonsmokers. The plasma cholesteryl ester transfer protein (CETP) mass was 17% higher in smokers as compared with controls (P < .05), but the endogenous CETP activity corrected for plasma triglycerides (TG) was in fact 57% lower in smokers than in controls (P < .01). Lipid transfer inhibitor protein activity was also similar in both groups. In conclusion, the habit of smoking induces a severe impairment of many steps of the RCT system even in the absence of overt dyslipidemia. Such an adverse effect might favor the atherogenicity of smoking.