Differential effects of portal diversion on hepatocyte function (HF) and hepatic reticuloendothelial cell (HRES) activity in the dog

Abstract

End-to-side portocaval shunts (PCS) were constructed in six dogs to evaluate the effect of complete portal blood flow diversion on hepatocellular structure and function, hepatic reticuloendothelial (RE) activity, and serum opsonic activity (OA). RE activity remained normal after PCS despite a 40% reduction in estimated hepatic blood flow. Tissue distribution of injected colloid shifted away from liver to spleen, lung, and bone marrow. OA decreased to 40% of baseline values 6 weeks after PCS and remained low. Postshunt changes in hepatic morphology primarily affected hepatocytes and included deglycogenation and loss of rough endoplasmic reticulum. Significant changes in Kupffer cell morphology were not observed. Complete portal flow diversion in the dog caused profound alterations in hepatocellular structure and function without compromising Kupffer cell phagocytic and metabolic activity. Kupffer cells may be less dependent than hepatocytes upon hepatotrophic factors contained in portal blood. OA did not correlate with changes in vascular lipid clearance, suggesting that either phagocytosis of RES test lipid in the dog is not dependent on prior opsonization, or that the assay used was neither sensitive nor specific enough to measure a critical opsonic threshold required for effective phagocytosis.