Cigarette smoking impairs hepatic uptake of high density lipoproteins

The effect of chronic inhalation of cigarette smoke on hepatic uptake of high density lipoproteins (HDL) in White Carneau pigeons was examined. Four treatment groups included: 1) Shelf Control birds fed a chow diet and retained in their cages; 2) Sham pigeons fed a cholesterol-saturated fat diet and exposed to fresh air by a smoking machine; 3) Low nicotine-low carbon monoxide (LoLo) animals also fed the cholesterol diet and exposed to low concentrations of these cigarette smoke products; and 4) High nicotine-high carbon monoxide (HiHi) birds fed the cholesterol diet and subjected to high concentrations of these components. Livers from both smoke exposed groups contained significantly more triglyceride than those from Sham animals while livers from HiHi birds alone had elevated concentrations of protein. Liver slices from LoLo and HiHi pigeons incorporated significantly less HDL 3H free and esterified cholesterol and HDL 14C apoprotein from media during in vitro incubation than livers from Sham birds. Impaired hepatic uptake of HDL suggests a permanent alteration in liver function resulting from chronic exposure to tobacco smoke and may represent one mechanism by which cigarette smoking attenuates HDL's anti-atherogenic properties.