HIDDEN ENDOTOXIN IN PLASMA OF PATIENTS WITH ALCOHOLIC LIVER-DISEASE

Objective: The results of several earlier studies suggest that previous methods used to determine endotoxin in the plasma of patients with acute or chronic liver disease fail to detect a substantial percentage of lipopolysaccharide (LPS) which is bound to plasma constituents. The aim of this study was to determine this 'hidden' fraction of LPS in the plasma of patients with alcoholic liver disease. Design and methods: LPS was determined in plasma samples from 43 patients with alcoholic liver disease (24 patients with cirrhosis and 14 with fatty liver or alcoholic hepatitis) and nine healthy controls using a chromogenic substrate test. The results obtained following standard pretreatment of the plasma by heating (method A) were compared with those following pretreatment by the addition of perchloric acid and dissolution of the precipitate by triethanolamine, a solvent for LPS, (method B) or addition of a detergent, Tween 80, after heating the plasma (method C). Results: Using the standard method (A), the groups with fatty liver or alcoholic hepatitis and the cirrhotics exhibited distinctly higher plasma LPS concentrations (16.5 +/- 4.8 and 12.3 +/- 2pg/ml, respectively) compared with those obtained in the controls (2.5 +/- 0.5pg/ml; P<0.01). The addition of Tween 80 (method C) resulted in a pronounced increase (P<0.01) in the concentration of LPS in patients with fatty liver or alcoholic hepatitis (52.1 +/- 13.3 pg/ml) and in cirrhotics (40.7 +/- 8.1 pg/ml), while only a small increase was observed in controls (6.25 +/- 1.8pg/ml). Using method B, a virtually identical increase in LPS concentration was observed in the cirrhotics (40.9 +/- 4.7pg/ml). The LPS concentrations revealed a significant negative correlation with the concentrations of HDL cholesterol, albumin and transferrin, three proteins which are capable of binding LPS in plasma. Conclusion: Plasma of patients with both mild and advanced alcoholic liver disease contains distinctly higher LPS concentrations than previously supposed.