Altered lipid composition and differential changes in activities of membrane-bound enzymes of erythrocytes in hepatic cirrhosis.

Lipid composition, fluidity, and Na+,K(+)-adenosine triphosphatase (ATPase), Mg(2+)-ATPase, and acetylcholinesterase (AChE) activities of erythrocyte membranes were examined in comparison to plasma lipid composition and lecithin:cholesterol acyltransferase (LCAT) activities in 39 patients with hepatic cirrhosis due to viral hepatitis (Child-Pugh class A, n = 12; class B, n = 13; and class C, n = 14). Plasma LCAT activities decreased and the plasma free-cholesterol to phospholipid molar ratio (C/PL) increased with progressive severity of hepatic cirrhosis. C/PL and fluorescence polarization (inverse of fluidity) of erythrocyte membranes also increased with disease progression (C/PL: Child-Pugh A, 0.911 +/- 0.010; B, 0.941 +/- 0.011; C, 0.979 +/- 0.028; and normal, 0.798 +/- 0.010; fluorescence polarization: Child-Pugh A, 0.348 +/- 0.002; B, 0.351 +/- 0.002; C, 0.355 +/- 0.002; and normal, 0.340 +/- 0.002). There was a correlation between C/PL and fluorescence polarization of erythrocyte membranes (r = .629, P < .001). Na+,K(+)-ATPase activity of erythrocyte membranes did not differ between cirrhotic patients and normal subjects. On the other hand, Mg(2+)-ATPase activity decreased in Child-Pugh C cirrhosis. AChE activity was decreased in Child-Pugh A cirrhosis, and decreased further in Child-Pugh B and C cirrhosis. AChE and Mg(2+)-ATPase activities correlated inversely with fluorescence polarization (r = -.652, P < .001 and r = -.381, P < .01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)