Susceptibility to in vitro lipid peroxidation of low density lipoproteins and erythrocyte membranes from liver cirrhotic patients.

ABSTRACT

The aim of the present study was to investigate the susceptibility of low density lipoprotein (LDL) and red blood cell membranes (RCM) from liver cirrhotic patients and control subjects, to the peroxidative stress, induced in vitro by phenylhydrazine. The susceptibility to peroxidation was determined by measuring the formation of the thiobarbituric acid reactive substances (TBARS) after incubation with phenylhydrazine. Moreover the levels of cholesterol (C) and phospholipid (PL) were evaluated in plasma and isolated LDL and RCM. A significant decrease in plasma C, LDL-C and RCM-C content (p < 0.001, p < 0.01 and p < 0.05 respectively) and RCM-PL content (p < 0.01) were found in cirrhotic patients compared to controls. The lower susceptibility to in vitro peroxidation was shown by the TBARS levels significantly lower in LDL and RCM from cirrhotic patients with respect to controls (p < 0.0001 for both of them). Moreover significant positive correlations were found between TBARS-LDL and LDL-C or LDL-PL (r = +0.72, p < 0.0001; r = +0.58, p < 0.001) and between TBARS-RCM and RCM-C (r = +0.35, p < 0.05) or RCM-PL (r = 0.37, p < 0.05) from combined patients and controls. Our data seem to ascribe the lower in vitro peroxidability to the lower levels of plasma lipids.