EFFECT OF HEPATIC VENOUS OUTFLOW OBSTRUCTION ON PORES AND FENESTRATIONS IN SINUSOIDAL ENDOTHELIUM

Abstract

The ultrastructure of pores and fenestrations in [rat] hepatic sinusoidal endothelial cells was examined following partial surgical occludion of the suprahepatic portion of the inferior vena cava. Within 12 h after partial obstruction of hepatic venous outflow, endothelial pores (< 0.1 .mu.m in diameter) and sieve plates in the distal halves of sinusoids were greatly reduced in number or were totally absent, and they were replaced by large fenestrations (< 1.0 .mu.m in diameter). Pores forming sieve plates may fuse to form large fenestrations. Sinusoidal hypertension and hypoxia associated with obstruction of hepatic venous outflow may alter the distribution of pores and fenestrations in sinusoidal endothelium.