Study of fluidity of low density lipoproteins from liver cirrhotic patients

Background and Aim: Liver disease is accompanied by major quantitative and qualitative modifications in plasma lipoprotein metabolism. Alterations in plasma lipoprotein composition and a lower susceptibility to in vitro perox idation of low density lipoprotein (LDL) and erythrocyte membranes have bee n observed in liver cirrhosis. The main objective of the present work was t o investigate LDL chemical composition and fluidity in liver cirrhosis usin g the fluorescence polarization (Pf) of the 1,6-diphenyl-1,3,5-hexatriene ( DPH) probe. Methods and Results: The chemical composition of LDL was studied in 12 cirr hotic patients and 22 controls by conventional methods and its fatty acid c omposition by gas chromatography LDL fluidity was determined by measuring t he DPH Pf values. A decrease in molecular order was demonstrated by the sig nificant (p<0.05) decrease in Pf values in the cirrhotics. Modifications ir ? LDL fluidity are correlated with its composition. A significant increase in triglyceride content (p<0.05), and significant increases in tryglyceride /protein and triglyceride/phospholipid ratios were observed in the cirrhoti cs. Conclusions: Our results demonstrate that the higher LDL fluidity of cirrho tic patients may be due to an increased triglyceride content. (C) 1999, Med ikal Press.