Modification of lipid composition of erythrocyte membranes in chronic alcoholism

Insight into the Molecular Mechanism of Surface Interactions of Phosphatidylcholines─Langmuir Monolayer Study Complemented with Molecular Dynamics Simulations

Mutual interactions between components of biological membranes are pivotal for maintaining their proper biophysical properties, such as stability, fluidity, or permeability. The main building blocks of biomembranes are lipids, among which the most important are phospholipids (mainly phosphatidylcholines (PCs)) and sterols (mainly cholesterol). Although there is a plethora of reports on interactions between PCs, as well as between PCs and cholesterol, their molecular mechanism has not yet been fully explained. Therefore, to resolve this issue, we carried out systematic investigations based on the classical Langmuir monolayer technique complemented with molecular dynamics simulations. The studies involved systems containing 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) analogues possessing in the structure one or two polar functional groups similar to those of DPPC. The interactions and rheological properties of binary mixtures of DPPC analogues with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol were compared with reference systems (DPPC/POPC and DPPC/cholesterol). This pointed to the importance of the ternary amine group in PC/cholesterol interactions, while in PC mixtures, the phosphate group played a key role. In both cases, the esterified glycerol group had an effect on the magnitude of interactions. The obtained results are crucial for establishing structure-property relationships as well as for designing substitutes for natural lipids.

The effects of taurine, hypotaurine, and taurine homologs on erythrocyte morphology, membrane fluidity and cytoskeletal spectrin alterations due to diabetes, alcoholism and diabetes-alcoholism in the rat

Taurine (TAU) and compounds representing a TAU analog (hypotaurine = HYTAU) or homolog (aminomethanesulfonic acid = AMSA, homotaurine = HMTAU) were tested for their counteracting effects against alterations in erythrocyte (RBC) morphology, membrane fluidity and cytoskeletal spectrin distribution due to diabetes, alcoholism and diabetes-alcoholism in male Goto-Kakizaki rats (made diabetic with a high fat diet and alcoholic upon feeding on a flavored alcohol solution) and Wistar-Kyoto rats (serving as controls). Both diabetes and alcoholism changed the RBC discoidal biconcave shape to a spiculated one, lowered membrane fluidity, and caused spectrin to become marginalized. While AMSA and HYTAU returned the RBC shape to normal, HMTAU made it only discoidal, and TAU was without effect. All test compounds, but TAU, maintained the membrane fluidity normal; and HYTAU and AMSA, but not TAU or HMTAU, kept spectrin uniformly distributed. The noted effects were correlated with compound structure and RBC values for malondialdehyde and cholesterol/phospholipid ratio.

Serum triglyceride and insulin levels are associated with erythrocyte sodium-lithium counter-transport activity in normoglycaemic individuals

The relationship between erythrocyte sodium-lithium counter-transport activity, serum insulin, lipids and demographic factors was examined in 93 normoglycaemic predominantly normotensive individuals with mild fasting hypercholesterolaemia (greater than 5.2 mmol/l). The major significant univariate correlates of sodium-lithium counter-transport activity were fasting serum triglycerides, HDL cholesterol, the ratio of fasting glucose: insulin, apo A1, alcohol consumption and apo B. Stepwise multiple regression analysis revealed 24% of the variability in sodium-lithium counter-transport activity could be accounted for by independent contributions of fasting serum triglycerides, alcohol consumption, the fasting glucose/insulin ratio and apo A1 and ANOVA confirmed a significant relationship with fasting insulin measures that was independent of serum triglycerides (P less than 0.05). The relationship between erythrocyte sodium-lithium counter-transport activity and concentrations of serum triglycerides, HDL components, insulin and additionally alcohol consumption, could reflect the influence of those variables on erythrocyte structure and function.

Abnormalities of hematologic parameters in heavy drinkers and alcoholics

Hematologic parameters measured by a Technicon H-1 analyzer and reticulocyte values were studied in three middle-aged male groups; 184 social drinkers, 88 heavy drinkers, and 106 alcoholics. Erythrocyte mean cell volume (MCV) correlated positively (p less than 0.001) with red cell distribution width (r = 0.388) and negatively with red blood cells (r = -0.594, p less than 0.001), hemoglobin distribution width (r = -0.330, p less than 0.001), cell by cell counted hemoglobin concentration (CHCM) (r = -0.434, p less than 0.001), and the ratio between standard deviation of CHCM and CHCM (r = -0.375, p less than 0.001). In spite of these correlations high red cell distribution width values were also found in alcoholic patients with normocytosis (MCV less than or equal to 96 fl). Alcohol induced abnormalities primarily in erythrocytes. The only significant abnormality in the heavy drinker group was a high value of erythrocyte MCV, which was found in 22.7%. In the alcoholic group the MCV value was high in 39.6%, and low erythrocyte values were detected in 16%. A high erythrocyte mean cell distribution width value indicating anisocytosis was found in 40.6% of the alcoholic group. In this material the specificities of these values were also good. The scatter cytogram for red blood cells did not give any valuable visual information in the abuser groups. Thus, certain abnormalities in the Technicon H-1 system parameters, even other than MCV, can be explained by alcohol abuse.