Lipid Peroxidation in Erythrocyte Membranes of Women with Benign and Malignant Neoplasms of the Endometrium

The content of primary and secondary products of membrane peroxidation, total cholesterol concentration, and relative microviscosity of erythrocyte membranes were measured in women with endometrial cancer and uterine leiomyoma. The content of conjugated dienes in erythrocytes was highest in female patients with malignant tumors of the endometrium. The relative microviscosity of erythrocyte membranes in patients with uterine leiomyoma and endometrial cancer was elevated in the zone of lipid—lipid and protein—lipid contacts.     

In Vitro Effect of Fucose-Specific Lectins on Rat Erythrocyte Membranes under Normal Conditions and during Toxic Stress

We studied the effect of various fucose-specific lectins on lipid peroxidation in rat erythrocyte membranes under normal conditions and during exposure to the toxic agent. Under normal conditions parameters of lipid peroxidation in erythrocyte membranes increased after treatment with lectins or cadmium nitrate. Lectins possess biological activity modulated lipid peroxidation in membranes of erythrocytes from experimental animals, which depended on the time of adaptation. Differences were revealed in the effect of bacterial and plant lectins on lipid peroxidation in erythrocytes treated with the test xenobiotic. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 10, pp. 410–413, October, 2005     

Damage to erythrocyte membranes as the mechanism for acrylate toxicity

Acute poisoning with acrylates (acrylamide and acrylonitrile) was associated with damage to erythrocyte membranes: early stages of acrylamide poisoning were characterized by impairment of the acid resistance of erythrocytes, while later terms of acrylate intoxication were accompanied by condensation of erythrocyte membranes. Activation of lipid peroxidation in blood plasma and erythrocytes was observed during the early stage of intoxication, while at later terms LPO intensity in erythrocytes decreased. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 12, pp. 646–648, December, 2006     

Merozoite release from Plasmodium falciparum-infected erythrocytes involves the transfer of DiIC₁₆ from infected cell membrane to Maurer's clefts

Merozoite release from infected erythrocytes is a complex process, which is still not fully understood. Such process was characterised at ultra-structural level in this work by labelling erythrocyte membrane with a fluorescent lipid probe and subsequent photo-conversion into an electron-dense precipitate. A lipophilic DiIC₁₆ probe was inserted into the infected erythrocyte surface and the transport of this phospholipid analogue through the erythrocyte membrane was followed up during 48 h of the asexual erythrocyte cycle. The lipid probe was transferred from infected erythrocyte membranes to Maurer’s clefts during merozoite release, thereby indicating that these membranes remained inside host cells after parasite release. Fluorescent structures were never observed inside infected erythrocytes preceding merozoite exit and merozoites released from infected erythrocyte were not fluorescent. However, specific precipitated material was localised bordering the parasitophorous vacuole membrane and tubovesicular membranes when labelled non-infected erythrocytes were invaded by merozoites. It was revealed that lipids were interchangeable from one membrane to another, passing from infected erythrocyte membrane to Maurer’s clefts inside the erythrocyte ghost, even after merozoite release. Maurer’s clefts became photo-converted following merozoite release, suggesting that these structures were in close contact with infected erythrocyte membrane during merozoite exit and possibly played some role in malarial parasite exit from the host cell.     

Oxidative stress and erythrocyte integrity in end-stage renal failure patients hemodialysed using a vitamin E-modified membrane

Oxidative stress has been implicated in a range of disease states, including end-stage renal failure treated with hemodialysis. Hemodialysis with vitamin E-modified membranes reduces lipid peroxidation, but the effect on erythrocyte integrity has not been determined. This study compared antioxidant defense parameters and the resistance of erythrocytes to free radical-mediated hemolysis in patients dialysed with cellulose acetate membranes at baseline and with a vitamin E-modified membrane (Excebrane Clirans; Terumo Corporation) for 13 wk. Resistance of erythrocytes to free radical attack was assessed in vitro using the peroxyl hemolysis test. The time to 50% hemolysis (T50%) increased significantly during the first 6 wk of Excebrane use (p < 0.05), but this parameter returned to baseline by 13 wk. Glutathione concentration and erythrocyte superoxide dismutase activity were unchanged during the study, but glutathione peroxidase activity increased from low levels at baseline and became significantly higher at 6 and 13 wk (p < 0.001). Total erythrocyte polyunsaturated fatty acid content and C18:2 level increased (p < 0.001) and saturated fatty acids (total, C16:0, C18:0, C22:0 and C24:0) decreased (p < 0.03). Total monounsaturated fatty acid content was unchanged. The increased resistance of erythrocytes to hemolysis, the increased glutathione peroxidase activity, and the increased degree of unsaturation of fatty acids in the erythrocyte membrane are compatible with a reduction of oxidative stress during hemodialysis with vitamin E-modified membranes.     

Changes in the Lipid Phase of Erythrocyte Membranes in Patients with Paranoid Schizophrenia

Considerable changes in the lipid phase of erythrocyte membranes were found in patients with paranoid schizophrenia. During exacerbation and remission of the disease the content of phosphatidylethanolamine decreases, while the amount of lysophosphatidylcholine decreases. These changes are accompanied by an increase in erythrocyte membrane microviscosity. Structural modification of the lipid phase in erythrocyte membranes in patients with schizophrenia is associated with intensification of lipid peroxidation.     

The association between erythrocyte internal viscosity, protein non-enzymatic glycosylation and erythrocyte membrane dynamic properties in juvenile diabetes mellitus.

The association of intracellular viscosity of red blood cells and the dynamic properties of erythrocyte membranes in children suffering from diabetes has been investigated by means of ESR spectroscopy. It has been revealed that the slight decrease in the ratio hw/hs of maleimide bound to membrane protein-SH groups of erythrocytes in diabetes may ensue from the enhanced membrane protein immobilization in the plane of lipid bilayer. These alterations were accompanied by a corresponding increase in the relative rotational correlation time (tau c) of iodoacetamide spin label, thus suggesting that the conformational changes in membrane proteins may occur at both the intrinsic and more exposed thiol groups. The membranes of diabetic red blood cells were more glycosylated than those of relevant controls, and the extent of glycosylation was found to correlate significantly with h + 1/h0 and tau c (r = -0.652, P < 0.01 and r = 0.609, P < 0.01). Further, the conformational alterations in erythrocyte membranes from diabetic subjects were accompanied by a significant increase in the mobility parameter (h + 1/h0) of haemoglobin molecules in diabetic erythrocytes. The latter changes correlated well with the enhanced intracellular viscosity of diabetic red blood cells and the level of glycosylated haemoglobin. We conclude that the alterations in membrane lipid-protein interactions together with the increased glycosylation-derived internal viscosity may consequently imply altered viscoelastic properties of erythrocyte membranes and, underlying the impaired deformability of red blood cells in the diabetic state, contribute to the development of late diabetic sequelae.     

Effect of zinc on carp (Cyprinus carpio L.) erythrocytes.

The effect of zinc exposure on some properties of the carp erythrocyte membrane was studied in vitro. Red blood cells plasma membranes were separated from other cellular membranes using a combination of differential and density gradient centrifugation. The purity of obtained plasma membrane preparations was determined by measuring the activity of the marker enzymes. Electrophoretic patterns of the main erythrocyte membrane proteins excluded their degradation during the isolation and purification procedure. Carp erythrocyte membranes, obtained from cells previously incubated with increasing ZnSO4 concentrations, were used to elucidate the effect of zinc ions on their physical and biochemical properties. Using fluorescent probes: 12-AS and TMA-DPH, we found that zinc ions reduced the fluidity of the lipid bilayer, both in the middle and near the aqueous interface. Moreover, it was observed that zinc had no significant influence neither on the Na,K-ATPase activity nor on the thiol groups content in the erythrocyte membrane. We also detected that incubation of erythrocytes with zinc lead to the marked decrease of hemolytic resistance of the cells. Our studies demonstrate that zinc at higher concentrations may be toxic to carp erythrocytes causing changes in the membrane fluidity and hemolytic resistance.     

Changes in the membrane permeability of erythrocytes during blood coagulation in vitro

It was established that permeability of erythrocyte membranes increases significantly during coagulation of blood in vitro. As a result, a certain amount of biosubstrates may pass into blood plasma from the erythrocytes. The increase of red cell membrane permeability in coagulation of blood is due to activation of free-radical oxidation of the cell lipid structures.     

Spectrin phosphorylation in senescent rat erythrocytes

The rates of phosphorylation and dephosphorylation of the erythrocyte cytoskeletal protein, spectrin, were analyzed in young and old rat erythrocytes. Endogenous membrane protein kinase activity was measured in age-seperated rat erythrocytes, and was found to decrease as a function of cell age. Membranes prepared from young and old erythrocytes contained comparable levels of protein phosphatase activity. Spectrin phosphatase activity was readily observed in erythrocyte membranes.Partially purified spectrin kinase and spectrin were prepared from membranes obtained from young and old erythrocytes, and the phosphorylation of the spectrin fractions was measured with the isolated kinases. The kinases prepared from young or old cells phosphorylated spectrin from young cells to the same extent. When spectrin from old cells was used as the substrate, it was phosphorylated ten-fold less extensively by the spectrin kinase prepared from old cells than by the spectrin kinase from young cells. This finding indicated that the decrased phosphorylation of spectrin observed in membranes prepared from age-separated red cells was due to a structural alteration in the spectrin.A structural basis for the decreased phosphorylation of spectrin in older erythrocytes was sought. Treatment of erythrocyte membranes with malonyldialdehyde, a product of lipid peroxidation which accumulates in erythrocyte membranes during senescence, adversely affected spectrin phosphorylation. The results presented here indicate that intramolecular derivatization of spectrin was sufficient to impair its function as a substrate for protein kinase.     

Some factors influencing structural and functional properties of erythrocyte membranes in pregnant women

Study of lipid peroxidation and antioxidant activity of blood serum and the properties of the erythrocyte plasma membrane during pregnancy showed that the level of lipid peroxidation reaches the maximum by delivery. A decrease in serum antioxidant activity at that time is one of the determinants of structural changes in erythrocyte membranes. These changes may be associated with increased membrane permeability for oxytocic substances before delivery. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 123, No. 1, pp. 26–28, January, 1997     

Decrease of the inhibition of lipid peroxidation by glutathione-dependent system in erythrocytes of non-insulin dependent diabetics

Summary The inhibition of lipid peroxidation of erythrocyte membranes by glutathione-dependent protection was studied in patients with non-insulin dependent diabetes mellitus. Incubation of red cells from diabetics with 1.5 mM t-butyl hydroperoxide resulted in a lipid peroxidation increase greater than that of normal controls. Glutathione-dependent and glutathione-independent protection against oxidative damage was examined using an artificial system, in which erythrocyte ghosts were incubated with t-butyl peroxide and dialysed hemolysate in the presence or the absence of 2 mM glutathione. The glutathione-dependent protection of hemolysate from diabetics was approximately 70% of that from normal controls.The results suggest that decrease in glutathione-dependent protection against lipid peroxidation, along with decrease in glutathione levels, increases oxidative damage in erythrocyte membranes taken from diabetic patients.Abbreviations GSH reduced form of glutathione - GSSG glutathione disulfide - TCA trichloracetic acid - SOD superoxide dismutase - GPX glutathione peroxidase - MDA malondialdehyde     

Influence of the ionophore A23187 on the plastic behavior of normal erythrocytes.

Previous studies have demonstrated that A23187, an ionophore which selectively transports divalent cations across cell membranes, has profound effects on human erythrocytes: it causes red cells to take up calcium; lose potassium, water, and ATP; convert from biconcave discs to echinocytes and spheroechinocytes; and become more rigid. The present study has explored the influence of calcium uptake induced by the ionophore on the behavior of individual erythrocyte membranes by the micropipette aspiration technique. Exposure of erythrocytes to calcium and A23187 for intervals of up to 30 minutes resulted in marked changes in membrane viscoelastic properties, including the development of increased resistance to aspiration. The most striking manifestation of altered membrane mechanics was apparent after 10 minutes on incubation. Cells pulled into the pipette for a few seconds and the extruded back into the medium retained the deformity imposed by the pipette for several seconds to a few minutes before regaining the form they manifested prior to initial aspiration. The calcium-induced changes in erythrocyte behavior observed in this study strongly support the concept that extrinsic proteins located inside the membrane provide mechanical support to the cell wall, and that increased levels of calcium cause precipitation or cross-linking of the proteins responsible for the increased resistence to deformation and recoil observed after aspiration into micropipettes.     

Erythrocyte susceptibility to lipid peroxidation in patients with coronary atherosclerosis

In recent years it has been reported that free oxygen radicals play an important role in the pathogenesis of degenerative diseases and that antioxidant vitamins such as vitamins E or C prevent their harmful effects. In this study, we evaluated the following: Erythrocyte susceptibility to lipid peroxidation; the role of erythrocyte glutathione (GSH) as an antioxidant; plasma lipid fractions; and the relationship between plasma lipid peroxides and antioxidant vitamin levels. Thiobarbituric acid-reactive substance (TBARS) levels were measured to determine the levels of plasma lipid peroxides and the susceptibility to lipid peroxidation when erythrocytes were stressed by hydrogen peroxide for 2 h in vitro. Erythrocyte TBARS production was significantly higher in patients with coronary atherosclerosis than in the controls. On the other hand, the levels of plasma high-density lipoproteins, vitamin C, vitamin E and erythrocyte GSH were significantly lower, and the levels of plasma total cholesterol, triglycerides, low-density lipoproteins and TBARS were significantly higher in the patients with coronary atherosclerosis than in the controls. In conclusion, our results indicate that erythrocytes from patients with coronary atherosclerosis are more susceptible to oxidation than those of controls and that these patients have lowered antioxidant capacity as revealed by decreased plasma levels of vitamins C and E.     

Aging of the erythrocyte. IX. Fluorescence studies on changes in membrane properties

Fluorescence studies of membranes prepared from density-separated red blood cells demonstrated an increase in lipid viscosity (judging from fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene and 1-aminonaphthalane-8-sulfonate and changes in the physical state of proteins (judging from tryptophan fluorescence intensity and polarization). These alterations may be partly due to lipid peroxidation. In vivo accumulation of products of this process in the membranes was confirmed. Changes were also found in the distribution pattern of cell populations of different mean age in a cell sorter, probably due to alterations in rheological properties of the erythrocytes.     

Detection of membrane fluidity in submitochondrial particles of platelets and erythrocyte membranes from Mexican patients with Alzheimer disease by intramolecular excimer formation of 1,3 dipyrenylpropane

It has been suggested that mitochondrial dysfunction and defects in membrane structure could be implied in AD pathogenesis. The aim of the present work was the study of membrane fluidity in submitochondrial platelet particles and erythrocyte membranes from Mexican patients. Blood samples were obtained from 30 patients with Alzheimer disease and 30 aged-matched control subjects. Membrane fluidity determinations were done using a very low concentration of the fluorescent dipyrenylpropane probe incorporated in both types of membranes. This probe is able to give excimer and monomer fluorescence, therefore it can be used to monitor fluidity changes in biological membranes. The data obtained showed that in submitochondrial particles from AD patients, the excimer to monomer fluorescent intensity ratio was lower (0.231 +/- 0.008) than aged-matched control subjects (0.363 +/- 0.014). Therefore, membrane fluidity was lower in AD samples. On the other hand, we found similar membrane fluidity in erythrocytes from AD patients and aged-matched controls: the fluorescent intensity ratios were 0.312 +/- 0.03 and 0.305 +/- 0.033, respectively. In addition, lipid peroxidation in submitochondrial particles and erythrocyte membranes was higher in AD samples than in aged-matched controls. These data suggest that submitochondrial platelet particles are more sensitive to oxidative stress than erythrocyte membranes.     

Effect of Blood Lipoproteins and Apolipoproteins A-I,C, and E on the Microviscosity of Erythrocyte Membranes

We studied in vitro modifying effect of high-density lipoproteins, low-density lipoproteins, very-low-density lipoproteins, and apolipoproteins A-I, C, and E on membrane structure of rat erythrocytes. Incubation of erythrocyte membranes with lipoproteins was accompanied by significant changes in the behavior of fluorescent probe pyrene in the hydrophobic membrane region. The regulatory effect of lipoproteins was probably realized via exchange of lipid components between these particles and erythrocyte membrane. Apolipoproteins probably had membranotropic activity. Apolipoproteins A-I, C, and E had various effects on biophysical properties of the lipid phase in erythrocyte membranes.     

Lipid peroxidation in cats experimentally infected with <Emphasis Type="Italic">Trypanosoma evansi</Emphasis>

The objective of this study was to evaluate the lipid peroxidation and the susceptibility of erythrocytes to in vitro peroxidation as indicators of oxidative damage in erythrocytes and their roles in the pathogenesis of anemia during experimental Trypanosoma evansi infection in cats. Animals were divided into two groups: control and infected with T. evansi. Seven cats were infected with 10⁸ trypomastigotes each, and parasitemia was estimated daily for 49 days by microscopic examination of smears. Hematological and biochemical parameters were evaluated for monitoring of the disease. Plasma lipid peroxidation (Thiobarbituric Acid Reactive Substances (TBARS)) and the susceptibility of erythrocytes to in vitro peroxidation were evaluated. Blood samples for analysis were collected at days 21 and 49 post-inoculation. TBARS level, indicated by MDA concentration, was higher in the infected group than in the control group in both analyzed periods, as well as the in vitro erythrocyte peroxidation (P < 0.001). The infected cats had variable degrees of regenerative anemia, which could be explained by the damage in erythrocyte membrane caused by lipid peroxidation.     

Membranotropic effect of low-intensity laser radiation of the blood

We have examined the effect of a low-intensity laser radiation (wavelength 630 nm, beam power 1 mW) on the aggregability of blood platelets, acidic tolerance of erythrocytes, and the structure of their membranes. Laser radiation suppressed platelet aggregability induced by ATP, epinephrine, collagen, platelet activating factor, and fibrinogen and enhanced the resistance of the erythrocytes. It decreased the microviscosity of lipid bilayer and of the membrane protein-lipid contact regions and slowed down lipid peroxidation. These findings attest to a direct membranotropic effect of laser radiation, which is particularly strong in the protein-lipid contact regions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 10, pp. 412–415, October, 1998     

Glycolipid and p 40 are the binding sites in the sheep erythrocyte and T-lymphocyte membrane responsible for rosette formation

By coupling the major glycoprotein and total glycolipid of the sheep erythrocyte membrane to agarose beads it could be demonstrated that only lipid-beads formed rosettes with peripheral blood lymphocytes. Lipid-beads and sheep erythrocytes formed double rosettes with peripheral blood lymphocytes. Trypsinization of lymphocytes destroyed the rosette formation with lipid-beads. Subfractionation of the lipid by thin-layer chromatography revealed 8 different subfractions, 3 of them when coupled to agarose beads showed rosette formation. When the lipid was coupled to radioactive albumin, a protein of molecular weight 40,000 was labeled in two T-lymphocyte plasma membranes but not in B-lymphocyte plasma membranes. It is concluded that a lipid-protein interaction, involving the lipid of the erythrocyte and the p 40 of the lymphocyte membrane, is responsible for rosette formation of T-lymphocytes.