High perfusion pressure damages the sieving ability of sinusoidal endothelium in rat livers.

Fenestrated endothelium lining liver sinusoids forms an ultrastructural sieve between blood and hepatocytes which at physiological perfusion pressures has previously been shown to shield hepatocytes from large triglyceride-rich chylomicrons. In the study reported in this paper, enlargement of endothelial fenestrae at high perfusion pressures has been confirmed and a concurrent increase in trapping of large chylomicrons by the liver noted. These findings suggest the importance of employing physiological perfusion pressures in studies designed to examine hepatic lipoprotein metabolism and also suggest a possible mechanism in the pathogenesis of fatty change seen in the "nutmeg" liver of chronic venous congestion.