Alterations in the erythrocyte plasma membranes in patients with alcohol-induced liver cirrhosis – preliminary results

INTRODUCTION: Conformations of membrane proteins, membrane fluidity of erythrocytes in patients with AILC were studied with the use of electron paramagnetic resonance and spectrophotometric methods. The concentration of substances reacting with thiobarbituric acid was also determined. The aim of the study was to recognize the nature, level and causes of changes in the structure of erythrocytary membrane observed in erythrocytes of patients compared to erythrocytes from healthy controls. MATERIAL AND METHODS: Spin labels: MSL and ISL binding covalently to thiol groups of membrane cytoskeleton proteins were used to analyse modifications occurring in erythrocytary membrane proteins. Doxyl derivatives of fatty acids: 5-DS, 12-DS and 16-DS binding hydrophobically to erythrocytary membrane were used as spin labels for the analysis of erythrocyte membrane lipid fluidity. RESULTS: Modification of membrane cytoskeleton proteins and increase of membrane lipids fluidity were observed in erythrocytes of the investigated patients. An increase of the concentration of substances reacting with thiobarbituric acid was also confirmed in the erythrocytes of AILC patients. CONCLUSIONS: Observed disorders in the structure of erythrocyte cytoskeleton proteins in patients, which might developed as a consequence of oxidative stress may be conformation changes in the structure of proteins which affect membrane cytoskeleton. The differences in the structure of membrane proteins could be associated with an increase in membrane lipids fluidity. Increased fluidity of erythrocyte membrane may be a result of disorders in protein-lipid interaction or membrane lipid peroxidation activity.