Protective mechanism of high-density lipoprotein against endotoxemia in chronic alcohol ingestion

In the present study, we evaluated the role of high-density lipoprotein (HDL) as an endotoxin-binding protein in chronically alcohol-fed rats. Although the blood endotoxin level was significantly elevated in chronic ethanol-loaded rats, compared with control rats, serum tumor necrosis factor (TNF), ALT, and lactate dehydrogenase were not elevated. Serum HDL and its endotoxin-binding capacity were significantly increased in chronic ethanol-loaded rats. When Kupffer cells isolated from control and chronic ethanol-loaded rats were cultured in the medium containing 3 to 30 mg/dl HDL and endotoxin (500 ng/ml), endotoxin uptake and TNF production of Kupffer cells were decreased in proportion to the concentration of HDL in the medium. These results suggest that the increase in endotoxin-binding capacity of HDL may serve as a protective mechanism against endotoxin in chronic ethanol-loaded rats.