Hepatocellular dysfunction occurs earlier than the onset of hyperdynamic circulation during sepsis

Abstract

Studies indicate that hepatocellular dysfunction occurs at 2 h after cecal ligation and puncture (CLP, i.e., sepsis model) despite the increased cardiac output (CO) and hepatic perfusion. It, however, remains unknown whether hepatocellular function is depressed earlier than the onset of hyperdynamic circulation in sepsis. To determine this, rats were subjected to sepsis by CLP. At .5, 1, 1.5, or 2 h after CLP, CO was measured by dye dilution. Hepatocellular function (i.e., maximum velocity of indocyanine green clearance and the efficiency of the active transport) was determined using an in vivo indocyanine green clearance technique. Microvascular blood flow was measured by laser Doppler flowmetry. To determine whether there is any association between hemodynamics and prostaglandins (PGs), plasma levels of PGE2 and PGI2 were measured by radioimmunoassay. The results indicate that hepatocellular function decreased significantly as early as 1.5 h after CLP. Cardiac output and microvascular blood flow in the liver and small intestine, however, increased and vascular resistance decreased at 2 h after CLP. Thus, hepatocellular dysfunction occurs earlier than the occurrence of hyperdynamic circulation during sepsis. Although circulating PGE2 levels were not altered, plasma PGI2 increased significantly at 2 h after CLP. The elevated circulating PGI2 levels, therefore, may be partially responsible for the decreased vascular resistance and increased tissue perfusion at 2 h after CLP. Our findings also suggest that cellular dysfunction, observed in the very early stage of sepsis, is not due to any hyperdynamic circulation/hypermetabolism-related events, but may be associated with the release of proinflammatory cytokines.