Hyperlipidemia Induced In Vitro Hypoosmotic Fragility of Rat Erythrocytes (original) (raw)
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PeerJ, 2015
Background and objectives. Red blood cells (RBC) are continuously exposed to oxidative agents, affecting their membrane lipid function. However, the amount of lipid in RBCs is higher than the lipids of the cell membrane, and includes triacylglycerols, which are no membrane components. We assumed that the extra lipids originated from lipoproteins attached to the cell surface, and we intended to analyse whether the size and composition of this lipid pool were affected by sex or diet. Experimental design. Adult male and female Wistar rats were fed control or cafeteria diets. Packed blood cells and plasma lipids were extracted and analysed for fatty acids by methylation and GC-MS, taking care of not extracting membrane lipids. Results. The absence of ω3-PUFA in RBC extracts (but not in plasma) suggest that the lipids extracted were essentially those in the postulated lipid surface pool and not those in cell membrane. In cells' extracts, there was a marked depletion of PUFA (and, in general, of insaturation). Fatty acid patterns were similar for all groups studied, with limited effects of sex and no effects of diet in RBC (but not in plasma) fatty acids. Presence of trans fatty acids was small but higher in RBC lipids, and could not be justified by dietary sources. Conclusions. The presence of a small layer of lipid on the RBC surface may limit oxidative damage to the cell outer structures, and help explain its role in the transport of lipophilic compounds. However, there may be other, so far uncovered, additional functions for this lipid pool.
Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1986
During prolonged fasting in lizard and rat, plasma levels of unesterified cholesterol (UC) and phospholipids (TPL) decreased and there were reductions and increases, respectively, in the molar ratios of lecithin (PC) to sphingomyelin (SPH) and UC to TPL. 2. Plasma lecithin: cholesterol acyltransferase (LCATase) activity in lizard and rat plasma was reduced during prolonged fasting. 3. Erythrocyte lipid composition for fasted animals was also characterized by a reduction in the molar ratio PC/SPH and an increase in UC/TPL, and in both species there were positive correlations between these molar ratios in red cells and those in plasma. 4. In both species these were changes in the morphology of the erythrocytes, and those from fasted rats showed alterations in osmotic fragility and permeability which correlated with alterations in lipid composition. 5. These results suggest that changes in plasma lipoprotein lipid composition, linked to reduced LCATase activity, may cause similar alterations in the lipid composition of red cell membranes leading to altered membrane properties.
Health, 2010
To evaluate the effects of high fat food consisted of tallow (19% of total diets) and cholesterol (2%) on modification of erythrocyte phospholipids, fatty acids composition and glutathione redoxsystem of male Wistar rats with alimentary dyslipidemia. The results demonstrated that after 30 and 180 days of high-fat feed erythrocyte phosphatidylinositol and phosphatidylcholine levels were reduced, phosphatidylserine were increased. Only on the 90 days of the experiment phosphatidylinositol level increased. In all growups the erythrocyte 18:0 saturated fatty acids and 20:4n6, 22:4n6 polyunsaturated fatty acids (PUFA) were increased. Deficit of n3 PUFA-20:5n3 and 22:6n3 after 90 and 180 days high fat feed promoted compensatory synthesis from 18:1n9 on 20:3n9. Erythrocyte maleic dialdehyde increased, glutathione level decreased in all groups of rats after fed with high-fat feed. Glutathione reductase and glutathione peroxidase activity decreased in erythrocytes after 30 and 180 days of high-fat feed. In conclusion: high-fat diet during 30-90 days started adaptive answer in lipids of membrane and glutathione redox-system. Important mechanism of adaptation of a cellular membrane to high-fat diet is increase major, structuring a membrane phosphatidylethanolamine and minor, most metabolic significant fractions phospholipids (phosphatidylinositol), keeps homeostasis of 18:2n6 and 22:6n3, 20:3n9 compensatory synthesis, decrease in activity of processes lipid peroxidation, activation of enzymes of redox-system glutathione. But prolonging the high-fat feeding (180 days and more) formed failure compensatory processes (dysadaptation). It is a risk factor of developmening atherosclerosis, diabetes, steatogepatitis and other diseases.
European Journal of Nutrition, 2010
Purpose To assess the effect of medium-chain fatty acid (MCFA)-rich mustard oil and polyunsaturated fatty acid (PUFA)-rich mustard oil on erythrocyte membrane composition and osmotic fragility in normal and hypercholesterolemic rats. Method Membrane composition was analyzed using standard kits. Osmotic fragility was determined using method described by Dacie and Lewis. Fatty acid composition of membrane was analyzed using gas chromatographic methods. Membrane shape analysis was performed using scanning electron microscope. Results Osmotic fragility data suggested that the erythrocyte membrane of hypercholesterolemic rats were relatively more fragile than that of the normal rat's membrane, which could be reversed with the addition of MCFA-and PUFA-rich oil in the diet. The increased plasma cholesterol in hypercholesterolemic rats could also be lowered by the experimental oils. There was also marked changes in the fatty acid composition of the plasma and erythrocyte membrane phospholipids. Polyunsaturated fatty acids decreased in the plasma of the hypercholesterolemic subjects were increased with the treatment of the experimental oils. Shape changes of the membrane holes were observed in the hypercholesterolemic condition, which was brought to normal shape with the administration of the experimental oils. Conclusion In conclusion, rat erythrocytes appear to be deformed and became more fragile in cholesterol-rich blood. This deformity and fragility was partially reversed by experimental oils by virtue of their ability to lower the extent of hypercholesterolemia.
…, 2009
A currently ongoing randomized trial has revealed that the Mediterranean diet, rich in virgin olive oil or nuts, reduces systolic blood pressure in high-risk cardiovascular patients. Here, we present a structural substudy to assess the effect of a Mediterranean-style diet supplemented with nuts or virgin olive oil on erythrocyte membrane properties in 36 hypertensive participants after 1 year of intervention. Erythrocyte membrane lipid composition, structural properties of reconstituted erythrocyte membranes, and serum concentrations of inflammatory markers are reported. After the intervention, the membrane cholesterol content decreased, whereas that of phospholipids increased in all of the dietary groups; the diminishing cholesterol:phospholipid ratio could be associated with an increase in the membrane fluidity. Moreover, reconstituted membranes from the nuts and virgin olive oil groups showed a higher propensity to form a nonlamellar H II structure that was related to an increase in phosphatidylethanolamine lipid class. These data suggest that the Mediterranean-style diet affects the lipid metabolism that is altered in hypertensive patients, influencing the structural membrane properties. The erythrocyte membrane modulation described provides insight in the structural bases underlying the beneficial effect of a Mediterranean-style diet in hypertensive subjects. (Hypertension. 2009;54:00-00.)
Frontiers in Physiology
Background: This study examines the effect of graduated hyperglycaemia on the state and oxygen-binding ability of hemoglobin, the correlation of phospholipid fractions and their metabolites in the membrane, the activity of proteolytic enzymes and the morphofunctional state of erythrocytes. Methods: Conformational changes in the molecule of hemoglobin were determined by Raman spectroscopy. The structure of the erythrocytes was analyzed using laser interference microscopy (LIM). To determine the activity of NADN-methemoglobinreductase, we used the P.G. Board method. The degree of glycosylation of the erythrocyte membranes was determined using a method previously described by Felkoren et al. Lipid extraction was performed using the Bligh and Dyer method. Detection of the phospholipids was performed using V. E. Vaskovsky method. Results: Conditions of hyperglycaemia are characterized by a low affinity of hemoglobin to oxygen, which is manifested as a parallel decrease in the content of hemoglobin oxyform and the growth of deoxyform, methemoglobin and membrane-bound hemoglobin. The degree of glycosylation of membrane proteins and hemoglobin is high. For example, in the case of hyperglycaemia, erythrocytic membranes reduce the content of all phospholipid fractions with a simultaneous increase in lysoforms, free fatty acids and the diacylglycerol (DAG). Step wise hyperglycaemia in incubation medium and human erythrocytes results in an increased content of peptide components and general trypsin-like activity in the cytosol, with a simultaneous decreased activity of µ-calpain and caspase 3. Conclusions: Metabolic disorders and damage of cell membranes during hyperglycaemia cause an increase in the population of echinocytes and spherocytes. The resulting disorders are accompanied with a high probability of intravascular haemolysis.