Despite advances in the management of septic patients, large number of such patients subsequently die from the ensuing multiple organ failure. This could be due to the fact that some of the subtle changes in cellular functions during early sepsis are not identified and consequently missed, leading to inadequate or delayed treatment of the septic patient. Our results have shown that hepatocellular dysfunction occurs very early during sepsis in the rat, which is associated with elevated levels of circulating TNF and Il-6. Administration of recombinant TNF-alpha in normal animals at a dose which does not alter hemodynamics, decreases hepatocellular function and increases plasma Il-6 levels. We, therefore, propose that TNF and/or Il-6 are responsible for producing hepatocellular dysfunction in early sepsis and that blockade of their production or biological activities will prevent or delay athe occurrence of hepatocellular dysfunction. In this regard, our hypothesis is that administration of pharmacologic agents (which downregulate TNF and IL-6) following the onset of sepsis, in conjunction with fluid resuscitation and excision of septic focus, attenuates the progressive deterioration of hepatocellular and other cell and organ functions and reduces sepsis-induced late mortality. Studies are proposed to determine; 1) the mechanisms by which hepatocellular function is depressed during early sepsis and whether neutralization of the biological activities of TNF and Il-6 with TNF-binding proteins (i.e., soluble TNF receptors ) and anti-IL-6 antibody prevents hepatocellular dysfunction; 2) whether pentoxifylline, ATP-MgC12, chemically modified heparin downregulates TNF and Il-6 and subsequently prevents hepatocellular dysfunction in early sepsis and, if so, the mechanism of the beneficial effects of these agents; 3) whether the proposed agents have any beneficial effect on other organ function such as renal and gut absorptive function and whether sepsis-induced mortality is reduced by the use of these pharmacologic agents in conjunction with fluid resuscitation and septic focus excision. Cecal ligation and puncture will be used to induce polymicrobial sepsis in the rat. Plasma levels of TNF, IL-6, cell- associated TNF and other selected mediators (i.e., PGE2, catecholamines corticosterone) will be measured. TNF and Il-6 gene expression, cAMP, cGMP, Ca2+, IP3, protein kinase C, and beta-adrenergic receptors will be determined in isolated Kupffer cells (KC) and/or hepatocytes. In situ hybridization will be used to localize TNF and Il-6 mRNAs. The hemodynamic parameters and cell and organ functions to be measured include hepatocellular, renal and gut absorptive function, hepatic and renal perfusion, cardiac output, and circulating blood volume.. Moreover, KC number will be reduced to determine whether KC are the major source of TNF and IL-6. Hepatocyte-KC co-culture will be used to determine if KC from septic animals decreases hepatocyte protein synthesis from normal animals. The proposed studies should provide useful information that allows us not only to better understand the mechanisms of heptocellular dysfunction in early sepsis, but also to identify and intercept it at an earlier time in the course of sepsis and thereby prevent subsequent multiple organ failure and late mortality.
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