Changes In Erythrocyte Membrane Research Articles

Biochemical changes in erythrocyte membrane in type 2 diabetes mellitus

This study aims to establish a link between the lipid composition of red blood cell membrane and serum to aid in the early diagnosis and treatment of patients with type 2 diabetes mellitus. Diabetic subjects with and without dyslipidemia were selected along with healthy control subjects. Biochemical changes in serum and erythrocyte membrane were compared in study groups. The lipid composition of membrane was significantly altered with increased cholesterol:Phospholipid ratio and decreased Na + K + -ATPase of membrane upon comparison with control subjects. Increased hyperglycemia with altered serum lipid composition in diabetes mellitus causes glycation of membrane enzymes this along with oxidative stress leads to decrease in activity of Na + K + -ATPase and other changes in erythrocyte membrane. Significant findings of the study: As the lipid level increases there is increased lipid peroxidation and the membrane composition gets altered.

Erythrocyte membrane changes of chorea-acanthocytosis are the result of altered Lyn kinase activity

AbstractAcanthocytic RBCs are a peculiar diagnostic feature of chorea-acanthocytosis (ChAc), a rare autosomal recessive neurodegenerative disorder. Although recent years have witnessed some progress in the molecular characterization of ChAc, the mechanism(s) responsible for generation of acanthocytes in ChAc is largely unknown. As the membrane protein composition of ChAc RBCs is similar to that of normal RBCs, we evaluated the tyrosine (Tyr)–phosphorylation profile of RBCs using comparative proteomics. Increased Tyr phosphorylation state of several membrane proteins, including band 3, β-spectrin, and adducin, was noted in ChAc RBCs. In particular, band 3 was highly phosphorylated on the Tyr-904 residue, a functional target of Lyn, but not on Tyr-8, a functional target of Syk. In ChAc RBCs, band 3 Tyr phosphorylation by Lyn was independent of the canonical Syk-mediated pathway. The ChAc-associated alterations in RBC membrane protein organization appear to be the result of increased Tyr phosphorylation leading to altered linkage of band 3 to the junctional complexes involved in anchoring the membrane to the cytoskeleton as supported by coimmunoprecipitation of β-adducin with band 3 only in ChAc RBC-membrane treated with the Lyn-inhibitor PP2. We propose this altered association between membrane skeleton and membrane proteins as novel mechanism in the generation of acanthocytes in ChAc.

Changes in Erythrocyte Membrane in Type-Ii Diabetes Mellitus with and without Dyslipidemia

Background: In Diabetes mellitus there is decreased number of pump units on the erythrocyte membrane, altered lipid – protein interaction, depleted membrane anionic charge and enzyme glycation and peroxidation which account for many abnormal complications. Method: Diabetes subjects with and without dyslipidemia were selected along with healthy control then we correlate the changes in serum and erythrocyte membrane. Result: The lipid composition of membrane is significantly increased with cholesterol:phospholipid ratio and Na + K + - ATPase of membrane was decreased when compared to control. Conclusion: Lipid composition disturbances along with increased hyperglycemia which causes glycation of enzymes and oxidative stress causes the decrease in activity of Na + K + -ATPase and other changes in erythrocyte membrane.

Impedance spectroscopy of human erythrocyte membrane: Effect of frequency at the spectrin denaturation transition temperature

Thermal analysis of suspension impedance was applied at various frequencies, f, to study the changes in erythrocyte membranes (EM) over the temperature interval 47–53 °C where spectrin denatures. At f < crossover frequency (cof1) a decrease in EM resistance at 49.5 °C (A peak) has been observed. At f > cof1, when the capacitive conductance of EM becomes dominant, a second peak appeared at 50.5 °C (anti-A peak). The amplitudes of A and anti-A peaks reversibly depended on the phosphorylation of EM proteins. In contrast to the A peak, the anti-A peak was totally eliminated by modifications of EM with reagents that reduce EM deformability, O sO 4 (0.4–1 mM) and putrescine (cytosolic concentration 1.5–2.0 mM).

Study of optical and nanostructural metal-induced changes in erythrocyte membranes by scattering and atomic force microscopy

The surface topography of erythrocyte membranes is studied by atomic force microscopy. Differences in fine structure of membranes are found. The structure of profiles of erythrocyte membranes modified by metals is smoother compared to unmodified erythrocytes. The autocorrelation function of irregularity pro-files of erythrocyte membranes and its parameter (the correlation length) are informative parameters of the action of toxic metals on the erythrocyte membrane surface. The content of metal in an erythrocyte membrane is determined from optical investigations of a suspension of membranes subjected to the action of lead and zinc ions. It is revealed that the luminescence of erythrocyte membranes is enhanced compared to reference data. The absorption spectra of erythrocyte membranes in the range 325–740 nm are calculated from the diffuse transmission and reflection coefficients of samples taking into account their luminescence. The possibility of determining the content of metals in erythrocyte membranes from optical measurements is demonstrated.

Prallethrin induced biochemical changes in erythrocyte membrane and red cell osmotic haemolysis in human volunteers

Changes in biochemical composition in erythrocyte membrane, erythrocytic osmotic haemolysis, and nitrite and nitrate levels in plasma were analyzed in 12 human volunteers who were exposed regularly to prallethrin, a type I pyrethroid mosquito repellent. The results revealed a decrease in cholesterol (C) and phospholipid (P) moieties in erythrocyte membrane with no consequent change in C:P ratio. Further, a significant decrease in the content of phosphatidyl serine suggested that PS is a sensitive phospholipid species to the pyrethroid action. Significant decrease in membrane lipid peroxidation and enhanced levels of nitrite and nitrate in plasma and erythrocyte indicate that increased generation and availability of nitric oxide might have rendered tolerance to erythrocyte membrane by protecting the cells from haemolysis. Increased NO(2) and NO(3) may be due to increased activity of nitric oxide synthase (NOS) and/or expression of isoforms of NOS. A possible involvement of free radical scavenging and antioxidant effects of nitric oxide might have contributed to the observed decrease in lipid peroxidation in the present study.

The effect of green tea in oxidative stress

Green tea, an infusion prepared with the leaves of Camellia sinensis is particularly rich in flavonoids, which are strong antioxidants. Tea drinking, by providing antioxidants, may become valuable in several oxidative stress conditions. Our aim was to evaluate the effect of green tea drinking on some factors reflecting the development of oxidative stress in plasma and in erythrocytes. The study was performed in 34 Portuguese subjects. We evaluated the total antioxidant status (TAS), the lipid peroxidation products-malonyldialdehyde (MDA) and malonyldialdehyde+4-hydroxy-2(E)-nonenal (MDA+4-HNE)-and the oxidative changes in erythrocyte membrane, namely membrane bound haemoglobin (MBH) and the band 3 profile. Analytical evaluations were performed after 3 weeks drinking 1l of water daily, and after 4 weeks drinking 1l of green tea daily. Tea was prepared daily at the same conditions of temperature, time of infusion and concentration. After green tea drinking, we found a significant reduction in serum levels of MDA and MDA+4-HNE and in the oxidative stress within the erythrocyte, as suggested by a significantly lower value of MBH and by changes in band 3 profile towards a normal mean profile, namely an increase in the band 3 monomer. A rise in the antioxidant capacity was also observed. Our data suggest for green tea drinking a beneficial effect, by reducing the development or the enhancement of oxidative stress and, therefore, protecting the individual for oxidative stress diseases. Moreover, we propose further studies about the value of band 3 profile and of MBH in providing a cumulative measurement of the effect of green tea drinking upon the oxidative stress in cells. Moreover, further studies are also needed, to clarify the effect of green tea consumption, the value of regular green tea consumption and the way it should be prepared to reach a healthy effect.

Finite Element Method Analysis of the Deformation of Human Red Blood Cells

An erythrocyte and a spherocyte are subjected to aspiration pressure with a micropipette and analyzed by the finite element method (FEM). The comparison of the erythrocyte and the spherocyte indicates that the y-direction displacement of the erythrocyte was larger than that of the spherocyte under the same aspiration pressure. The x-direction stress distributions show that it is easier to change the shape of the erythrocyte model than that of the spherocyte model because a force in the opposite direction appears in the erythrocyte. This force seems to move the erythrocyte membrane to its center. The results indicate that the shape of the erythrocyte membrane changes partially under aspiration pressure at the point of contact with the micropipette and aspiration pressure. The results also indicate that the shape of the spherocyte membrane changes under aspiration pressure, but not only at a point of contact with the micropipette and the area subject to aspiration pressure; the entire spherocyte membrane seem to change the shape.

Damage to human erythrocytes by radiation-generated HO* radicals: molecular changes in erythrocyte membranes.

The effectiveness of radiation-generated HO* radicals in initiating erythrocyte hemolysis in the presence of oxygen and under anaerobic conditions and prehemolytic structural changes in the plasma-erythrocyte membrane were studied. Under anaerobic conditions the efficacy of HO* radicals in induction of hemolysis was 16-fold lower than under air. In both conditions, hemolysis was the final consequence of changes of the erythrocyte membrane. Preceding hemolysis, the dominating process under anaerobic conditions was the aggregation of membrane proteins. The aggregates were principally formed by -S-S- bridges. A decrease in spectrin and protein of band 3 content suggests their participation in the formation of the aggregates. These processes were accompanied by changes in protein conformation determined by means of 4-maleimido-2,2,6,6-tetramethylpiperidine-N-oxyl (MSL) spin label attached to membrane proteins. Under anaerobic conditions, in the range of prehemolytical doses, the reaction of HO* with lipids caused a slight (10-16%) increase in fluidity of the lipid bilayer in its hydrophobic region with a lack of lipid peroxidation. However, in the presence of oxygen, hemolysis was preceded by intense lipid peroxidation and by profound changes in the conformation of membrane proteins. At the radiation dose that normally initiates hemolysis a slight aggregation of proteins was observed. Changes were not observed in particular protein fractions. It can be suggested the cross-linking induced by HO* radicals under anaerobic conditions and a lack of lipid peroxidation are the cause of a decrease in erythrocyte sensitivity to hemolysis. Contrary, under aerobic conditions, molecular oxygen suppresses cross-linking, catalysing further steps of protein and lipid oxidation, which accelerate hemolysis.

Influence of aerobic oxidation of mouse erythrocytes on their recognition by macrophages.

Membrane protein modification can change cell surface properties which can be correlated with altered macrophage-erythrocyte interactions. Mouse erythrocytes were incubated in phosphate buffer for different times to induce protein modification. Mouse erythrocyte membrane changes were analyzed by infrared analyses and gel electrophoresis. Proteolytic digestion of membrane proteins was observed. After 22 hours preliminary incubation, the number of erythrocytes adhering to a monolayer of macrophages reached a maximum, the majority of which had not been phagocytosed. Most of the erythrocytes incubated for 40 hours underwent phagocytosis after adhesion to the macrophages.

Spectrofluorometric and microcalorimetric study of the thermal poration relevant to the mechanism of thermohaemolysis

This study sheds light on the structural changes in erythrocyte membrane during thermally induced poration, an event involved in thermohaemolysis. Two major membrane disturbing events can be induced during transient heating, the denaturation of spectrin and thermoporation. The first one precedes the latter but is not involved in it. Ethanol linearly reduces the onset temperature of both events but with different efficiencies. Thermoporation efficiency exceeds by 3.5 fold that of spectrin denaturation. Thus, at a specific concentration of ethanol (18% v/v), the poration occurs at 39.5 C, which precedes the denaturation of spectrin by 6 C. To induce and study the poration avoiding spectrin denaturation, cells were put in contact with preheated (39 C) isotonic (60mM) NaCl) media containing 18% v/v ethanol and sucrose as an osmotic protectant. After 3 min heating, the porated cells were washed, their membranes isolated and studied. The control cells were processed similarly except that they were incubated at 23 C, thus avoiding thermoporation. Using scanning microcalorimetry, the enthalpy and the temperature of denaturation of spectrin were found to be the same in control as well as in porated membranes which indicates similar spectrin structure in both membranes. While the enthalpy of denaturation of the anion channel was preserved, its denaturation temperature was lowered by 2.5 C after poration. These results confirmed that the heat denaturation of the main membrane proteins was not needed and not involved in thermoporation and, hence, in thermohaemolysis. Analysis of the fluorescence of membrane bound ANS gave an apparent increase in the number of binding sites for ANS in membranes after poration. In relation to the control, the eximerization of pyrene in porated membranes changed, depending on the location of the probe: in the domain of free lipids it decreased by 18% but it increased by 60% in the lipid milieu proximal to membrane proteins. Likewise, the eximerization of N-(3-Pyrene) maleimide bound to membrane proteins increased by 67% after poration, which proves increased intramolecular mobility of proteins following poration. The maximal efficiency for transferring energy from tryptophans to neighbouring pyrene was determined to be 0.93 in control, which is almost the same as in intact membranes, and 0.70 in porated membranes, indicating a strong decrease in the lipid/protein contact zone. This data suggests a mild conformational change, possibly an irreversible perturbance of the transbilayer distribution of membrane proteins in porated membranes in comparison to the control and intact ones.

Effect of Stobadine on Carbon Tetrachloride-Induced Erythrocyte Membrane Changes in Rats

Our previous study showed that stobadine is effective against ischemia/reperfusion-induced gastric mucosal injury. The present study examined the ability of stobadine to protect erythrocyte membrane against free radical injury after long-term carbon tetrachloride (CCl 4) application. The erythrocyte membrane changes were established using colloid-osmotic hemolysis. The significant increase of colloid-osmotic hemolysis was found in animals treated with CCl 4. CCl 4 also increased formation of thiobarbituric acid-reactive substances (TBARs) and decreased thiol group content. Stobadine in both doses (10.0 and 20.0 mg · kg −1) protected erythrocyte membrane against CCl 4-induced injury. The membrane lipid bilayer is the most affected part of the erythrocyte membrane. In presence of stobadine, CCl 4-induced lipid peroxidation was partially or totally prevented whereas the level of total membrane thiols was increased. Based on these results, it can be concluded that protective effect of stobadine on CCl 4-induced erythrocyte membrane changes should be related to its antioxidant properties.

Haematological and erythrocyte membrane changes induced by methacrylonitrile

The effect of methacrylonitrile (MeAN) a cyanogen compound, on various haematological parameters was studied. Administration of MeAN at 100 mg/kg per body weight/day for 7 days resulted in a significant decrease in the red cell count and in the level of hemoglobin, probably by inducing hemolysis. MeAN altered the fluidity of the erythrocyte membrane by increasing membrane cholesterol while the phospholipid remained unchanged, followed by a decrease in the activities of membrane bound enzymes like (Na +, K +)-ATPase, Acetylcholine esterase and NADH-dehydrogenase. A significant decrease in membrane sialic acid and calcium were also observed in the treated animals. MeAN besides having various toxic side effects, also exerts its toxicity on the circulating erythrocytes.

EFFECTS OF THYMOSIN ALPHA-1 ON ERYTHROCYTE LIPID LEVELS AND ERYTHROCYTE MEMBRANE (Na+-K+) -ATPase ACTIVITY IN EXPERIMENTAL HYPERCHOLESTEROLEMIA

Thymosin alpha-1 is an active polypeptide isolated from thymus. This polypeptide is widely used in the diagnosis and treatment of many diseases, especially immune diseases. In this present study, we examined the effects of thymosin alpha-1 on plasma and erythrocyte lipid levels and the changes in erythrocyte membrane (Na+, K+)ATPase activity in hypercholesterolemic rabbits. The erythrocyte lipid levels decreased, whereas the erythrocyte membrane (Na+, K+)ATPase activity increased significantly in these rabbits after thymosin alpha-1 injection. These findings suggest that thymosin alpha-1 is effective on both the lipid level and erythrocyte membrane (Na+, K+)ATPase activity.

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.

Dielectrophoretic detection of changes in erythrocyte membranes following malarial infection

The dielectric properties of normal erythrocytes were compared to those of cells infected with the malarial parasite Plasmodium falciparum. Normal cells provided stable electrorotation spectra which, when analyzed by a single-shelled oblate spheroid dielectric model, gave a specific capacitance value of 12±1.2 mF/m 2 for the plasma membrane, a cytoplasmic permittivity of 57±5.4 and a cytoplasmic conductivity of 0.52±0.05 S/m. By contrast, parasitized cells exhibited electrorotation spectra with a time-dependency that suggested significant net ion outflux via the plasma membrane and it was not possible to derive reliable cell parameter values in this case. To overcome this problem, cell membrane dielectric properties were instead determined from dielectrophoretic crossover frequency measurements made as a function of the cell suspending medium conductivity. The crossover frequency for normal cells depended linearly on the suspension conductivity above 20 mS/m and analysis according to the single-shelled oblate spheroid dielectric model yielded values of 11.8 mF/m 2 and 271 S/m 2, respectively, for the specific capacitance and conductance of the plasma membrane. Unexpectedly, the crossover frequency characteristics of parasitized cells at high suspending medium conductivities were non-linear. This effect was analyzed in terms of possible dependencies of the cell membrane capacitance, conductance or shape on the suspension medium conductivity, and we concluded that variations in the membrane conductance were most likely responsible for the observed non-linearity. According to this model, parasitized cells had a specific membrane capacitance of 9±2 mF/m 2 and a specific membrane conductance of 1130 S/m 2 that increased with increasing cell suspending medium conductivity. Such conductivity changes in parasitized cells are discussed in terms of previously observed parasite-associated membrane pores. Finally, we conclude that the large differences between the dielectrophoretic crossover characteristics of normal and parasitized cells should allow straightforward sorting of these cell types by dielectrophoretic methods.

Red blood cell aggregation and primary hyperlipoproteinemia

Erythrocyte aggregation (EA) was determined in a Myrenne aggregometer at stasis (EAM o) and low shear (EAM 1) in 102 patients suffering from primary hyperlipoproteinemia (PHLP)-46 with familial hypercholesterolemia (FH); 28 with familial combined hyperlipemia (FCHL); 28 with primary hypertriglyceridemia (PHTG)-and in a control group (CG) of healthy matched subjects. EA was also determined in FH after the autologous plasma had been replaced by a control plasma. The following parameters were also measured: fibrinogen (Fbg), plasmatic lipids, apolipoproteins, glucose, HbA 1c and membrane erythrocyte lipids: cholesterol (C) and phospholipids (PL). An increase in both EAM o and EAM 1 was observed in all the studied groups of patients. When erythrocytes of FH were resuspended in control plasma, EA normalized, but only in 75 % of them. Fbg was elevated only in FH and FCHL. Membrane C was increased mainly in FH and FCHL. EA correlates with both Fbg and apolipoproteins. In FH, EA also correlates with membrane C/PL. In addition, a high significant correlation exists between EA and HbA 1c in FCHL. The results obtained suggest that not only Fbg and apolipoproteins but also possible changes in erythrocyte membrane could encourage EA in PHLP.

Changes in erythrocyte membranes after fractioned hyperthermia

The structural changes in erythrocytes membranes were examined before and after the second heat shock of erythrocytes. Electrophoretic separation of protein erythrocyte membranes for cells incubated at 48.5°C was different from control i.e. from erythrocytes incubated at 37°C. No quantitative or qualitative changes were spotted in comparison with protein membranes isolated from the erythrocytes following single or double heat shock. Fluidity of erythrocytes membranes was determined by using spin labels, 5-doxylstearic acid and 16-doxylstearic acid. The membranes were more rigid in their hydrophobic regions after incubation of cells at 44°C. It can be suggested that erythrocyte membranes play some role in thermotolerance and heat damage of enuclate cells.

Erythrocyte membrane changes of individuals with Down's Syndrome in various stages of Alzheimer-type dementia

An increase in erythrocyte-bound IgG, enhanced breakdown of band 3, and changes in erythrocyte anion transport characteristics are observed in individuals with Down's Syndrome. We interpret these data as indicative for a disturbance of normal erythrocyte aging. A comparison of three groups of individuals with Down's Syndrome in various stages of dementia of the Alzheimer type did not reveal a correlation between the erythrocyte membrane changes and age or stage of dementia. Considering previously obtained data on patients with senile dementia of the Alzheimer type (7), these results may signify that parameters of disturbed erythrocyte aging represent presymptomatic markers of Alzheimer-type dementia.

Molecular changes in erythrocyte membranes induced by long-term administration of clofibrate

It has been reported that an enantiomer ((S)-(−)-4) of clofibric acid, and the racemate, can block the chloride conductance of skeletal muscle membrane. It has also been reported that several analogs of clofibric acid inhibit the HCO 3 −Cl − exchange of erythrocytes. Since the two effects are probably similar biophysical membrane phenomena, the possibility of a common molecular mechanism arises. We exposed Sprague-Dawley male rats to long-term administration of clofibrate and 20,25-diazacholesterol (20,25-D) for comparison, at equipotent doses. Clofibrate (but not 20,25-diazacholesterol) produced a significant increase in density of the 220,000 Da band (β-spectrin) and a decrease, also significant, in density of bands 2.1, 2.2, 2.3, 2.6 (syndeins or ankyrins) and of bands 4.1 and 6. Thus, clofibrate exhibits a manifold effect on the protein profile of the erythrocyte membrane cytoskeleton which, due to the lack of effect of 20-25-D, does not seem to be produced by the hypolipidemic effect per se, and thus deserves further study.