Properties Of Erythrocyte Membrane Research Articles

Effect of ichphans on the structural properties of erythrocyte membrane

Morphological transformation of erythrocytes and structural changes in the erythrocyte membrane have been revealed by scanning electron microscopy and spin-probe technique. These effects were caused by the incorporation of ichphans, new generation drugs combining antioxidant and anticholinesterase effects, into the erythrocyte membrane and their distribution in the intramembrane space. Different distribution and modulatory effect of the derivatives with different hydrophobic properties have been shown. The derivatives with 8 and 10 carbon atoms in the aliphatic substituent were the most efficient modifiers of the membrane structure and morphology of erythrocytes.

Dynamic and electrokinetic behavior of erythrocyte membrane in diabetes mellitus and diabetic cardiovascular disease

The dynamic and electrokinetic properties of erythrocyte membrane are explored as significant indices involved in the association of diabetes and diabetic cardiovascular disease. Lipid peroxidation studies reveal malondialdehyde concentration to reach a maximum in diabetic cardiovascular patients. Lower fluidity of erythrocyte membrane implies declined ability of erythrocyte to deform in pathogenic state, which is supported by decreased osmotic resistance. Membrane protein profile modification detected by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicates a significant reduction in the quantity of ankyrin protein band 2.1 in diabetic subjects. In addition the reduction in an immunoreactive band against polyclonal anti-ankyrin antibody during Western blot analysis confirms the modification of ankyrin protein in diseased erythrocyte (reported for the first time). The electrokinetic behavior of erythrocyte membrane is monitored by laser Doppler velocimetry mode of the Nano-ZS. Changes in zeta potential values of the red blood cell membrane are consistent with decreased membrane fluidity in diseased erythrocytes (reported for the first time). Membrane potential values of control, diabetic and diabetic cardiovascular erythrocytes are −37.24±1.5 mV, −28.44±1.34 mV, and −22.21±1.21 mV respectively indicating a gradual lowering of zeta potential when erythrocyte membrane undergoes progressive changes – from simple agglomeration to fluid gel formation – and finally to a rigid gel.

Effects of a synbiotic containing Lactobacillus acidophilus ATCC 4962 on plasma lipid profiles and morphology of erythrocytes in hypercholesterolaemic pigs on high- and low-fat diets

The aim of this study was to evaluate the effect of a synbiotic containing Lactobacillus acidophilus ATCC 4962, fructooligosaccharide, inulin and mannitol on plasma lipid profiles and erythrocyte membrane properties in hypercholesterolaemic pigs on high- and low-fat diets. Twenty-four white male Landrace pigs were randomly allocated to four treatment groups for 8 weeks (n 6). Treatment factors were the supplementation of synbiotic (with and without) and dietary fat (5 and 15 %). The supplementation of synbiotic reduced plasma total cholesterol (P = 0.001), TAG (P = 0.002) and LDL-cholesterol (P = 0.045) for both dietary fats. A higher concentration of esterified-cholesterol in HDL of pigs supplemented with synbiotic than the control regardless of dietary fat (P = 0.036) indicated that cholesterol was reduced in the form of cholesteryl esters. Reduced concentration of cholesteryl esters (P < 0.001) and increased concentration of TAG (P = 0.042) in LDL of pigs on synbiotic suggested that LDL-cholesterol was reduced via the hydrolysis of smaller and denser LDL particles. The erythrocytes of pigs without any synbiotic showed more prevalence of spur cells than those given the synbiotic, as supported by the higher cholesterol: phospholipid ratio in erythrocytes (P = 0.001). Also, membrane fluidity and rigidity were improved as supported by the decreased fluorescence anisotropies in the Hb-free erythrocyte membrane of pigs given synbiotic (P < 0.001). The administration of the synbiotic reduced plasma TAG, total cholesterol and LDL-cholesterol in hypercholesterolaemic pigs, possibly in the form of cholesteryl esters, via the interrelated pathways of lipid transporters (VLDL, LDL and HDL). The synbiotic also reduced deformation of erythrocytes via improved membrane fluidity and permeability.

Erythrocyte remodeling by malaria parasites

Plasmodium falciparum causes the most virulent form of human malarias. It is a protozoan parasite that infects human erythrocytes and the erythrocytic stages are responsible for all symptoms and pathologies of the disease. Critical to infection is the formation of a parasitophorous vacuolar membrane at the time of entry and within which the intracellular parasite proliferates. Since erythrocytes lack endocytic machinery, it is surprising that they can be infected by pathogens. This review summarizes recent studies of the erythrocyte-malaria interaction that have provided insights into properties of erythrocyte membranes as well as parasite mechanisms that remodel the erythrocyte. Themes revealed by recent literature suggest that both parasite and erythrocyte components regulate parasite entry and intracellular growth by extensively remodeling host membranes. These remodeling events include the invagination of the host cell membrane during parasite entry that results in the creation and maintenance of a vacuole that surrounds the intracellular organism, and the development of antigenic, structural and transport alterations during intracellular parasite development. The implications are that malarial erythrocyte remodeling events occur at a significant cost to the human host since many of the associated virulence events have been linked to severe disease pathologies.

Effect of peroxynitrite on mechanical properties of human erythrocyte membranes

Atomic force microscopy showed that treatment of human whole blood with peroxynitrite modified local mechanical and physical characteristics of erythrocyte membranes, specifically, increased their rigidity.

Impaired Filterability of Erythrocytes from Patients with Chronic Hepatitis C and Effects of Eicosapentaenoic Acid on the Filterability

Although erythrocyte filterability plays a key role in microcirculation, it is unknown whether the filterability of erythrocytes from patients with chronic hepatitis C (CH-C) is impaired. This study aimed to investigate erythrocyte filterability in CH-C patients in relation to medical treatment. The mean erythrocyte filterability (%) for all 24 patients with CH-C (69.2 +/- 10.8%) was significantly lower than that for 5 normal controls (80.5 +/- 1.7%, P < 0.03). In 8 patients, the combination therapy of ribavirin (RBV) and interferon improved liver function but caused anemia. The filterability after treatment (57.8 +/- 12.8%) was lower than that before treatment (70.8 +/- 9.7%, P < 0.05). Decreased filterability showed no correlation with the mean corpuscular volume or mean corpuscular Hb concentration during treatment, suggesting that the decrease in filterability mainly arises from changes in erythrocyte membrane properties. We investigated the protective effects of eicosapentaenoic acid (EPA) on the RBV-induced anemia. Filterability in 7 responders was markedly improved from 68.4 +/- 4.6% to 77.4 +/- 2.4% (P < 0.001), but not in 3 nonresponders. In the responders, the progression of anemia was restrained. In conclusion, we found an obvious impairment of the filterability of erythrocytes from CH-C patients, further impairment of the filterability induced by oxidative membrane damage caused by RBV leading to hemolytic anemia, and amelioration of the filterability caused by the antioxidative effects of EPA.

In vitro effects of oxygen on physico-chemical properties of horse erythrocyte membrane

Whether direct exposure to different concentrations (0%, 13%, 100%) of oxygen may affect horse erythrocyte membrane fluidity (EMF) and fatty acid (FA) composition was studied during 1 ( T60) and 2 h ( T120) exposure. EMF was investigated at the head group level and hydrophobic core thanks to phosphorus nucleus 31 ( 31P) nuclear magnetic resonance ( 31P NMR) and electronic paramagnetic resonance (EPR) using two spin probes: 5-nitroxydestearic acid and 16-doxylstearic acid. Lipid structure of the membranes was studied by gas liquid chromatography. 4-Hydroxy-2 E-nonenal was also analyzed as a marker of lipid peroxidation. It increased at T120 13% and 100% oxygen whereas there were no significant changes in membrane dynamic or structure. Correlation was demonstrated between EMF and partial pressure of oxygen in the blood ( P O 2 ). In vitro high rate of oxygenation was efficient to induce lipid peroxidation but did not change membrane dynamics. This may be due to a low free radical production in vitro or to the high red blood cells antioxidant properties.

PECULIARITIES OF POIKILOCYTOSIS INDUCED BY REACTIVE NITROGEN SPECIES ACTION

The changes in a shape, a structure and mechanical properties of erythrocyte membrane after the treatment of whole human blood with peroxynitrite were studied by the methods of light, electron scanning and atomic force microscopy. The primary mechanisms of the changes in erythrocyte shape (acanthocytosis and spherocytosis) at the action of reactive nitrogen species state to be lipid phase separation as a result of lipid peroxidation and spectrin aggregation.

Investigation of the alterations induced in erythrocyte membrane physical characteristics of non-insulin-dependent type II diabetic Patients: an ESR study

The physical and dynamic properties of intact erythrocyte membranes of two groups, diabetic patients treated by diet alone (27 women and 41 men, 40–75 years old) and healthy subjects (controls) (25 women and 35 men, 35–75 years old) were investigated by electron spin resonance (ESR) spectroscopy. 5-doxyl stearic acid (5-DSA) and 4-maleimido-2,2,6,6-tetramethyl-piperidine-1-oxyl (MAL-6) are employed as spin labels throughout the experiments. While 5-DSA monitors the membrane surface region and gives information about the order of lipids in this region through the order parametersS′, MAL-6 binds thiol groups S-H to the membrane protein and gives information about possible protein conformational changes. Order parameters were calculated from room temperature spectra recorded for intact erythrocytes labeled with 5-DSA and the values of 0.682±0.004 and 0.666±0.004 were obtained for diabetic patients and controls, respectively. Variations of theh(−1),h(0),h(+1) and 2A11 parameters in the temperature range of 10–50 °C were also studied and fairly different behaviors were observed for both groups, especially for theh(−1) parameter. Line intensitiesW andS characterizing the concentrations of weakly and strongly immobilized MAL-6 species bound to S-H groups of intact erythrocyte membrane proteins were used to calculate theW/S ratios. They were found to be 34.1±1.9 and 30.5±2.4 for diabetic patients and controls, respectively. While line intensitiesT, those of theM1=−1 high-field resonance line associated with the weakly immobilized S-H sites, of both groups exhibit a very similar microwave saturation behavior in the range of 0.5–20 mW, line intensitiesW of both groups saturated differently. Variations of line intensitiesS, W andT with temperature were also investigated in the temperature range of 10–50 °C and characteristic differences were observed to exist between two groups implying a less fluid erythrocyte membrane for diabetic patients. Increases in the order parameterS′ and in theW/S ratio are considered as major factors attributable to the alteration in the physical and dynamic properties of erythrocyte membrane in the diabetic state.

Betaine prevents loss of sialic acid residues and peroxidative injury of erythrocyte membrane in ethanol‐given rats

To evaluate chronic ethanol toxicity on erythrocyte membrane and preventive action of betaine as a methyl donor, 24 male Wistar albino rats were divided into three groups: control, ethanol and ethanol plus betaine group. Animals were fed 60 ml diet per day for two months. Rats in the ethanol group were fed ethanol 8 g/kg/day. The ethanol + betaine groups were fed ethanol plus betaine (0.5% w/v). After two months, all animals were killed. Malondialdehyde (MDA) and sialic acid (SA) levels were determined in plasma samples. Osmotic fragility tests were performed on whole blood samples and erythrocyte membrane thiol contents were determined using membrane suspensions. Plasma MDA levels in ethanol-given rats were increased significantly compared to the control group of rats (p < 0.05). MDA in the betaine group was significantly lower than that in the ethanol group (p < 0.05). Erythrocyte membrane thiol contents in ethanol group were decreased compared with those of the control group (p < 0.05). Thiol contents were increased slightly after betaine therapy, but this increase was not statistically significant (p > 0.05). Plasma sialic acid levels in the ethanol group were significantly higher than in the control group (p < 0.05). Sialic acid was decreased in the betaine group compared to the ethanol group (p < 0.05). In the osmotic fragility test, we observed that chronic ethanol consumption increased erythrocyte hemolysis. Betaine protected against ethanol-induced hemolysis. Our findings show that chronic ethanol administration affects erythrocyte membrane properties and this may be related to oxidative stress. Betaine protects erythrocyte membrane alterations against chronic ethanol toxicity. Therefore betaine as a nutritional agent, may protect ethanol induced clinical problems associated with membrane abnormalities.

Decreased membrane fluidity and altered susceptibility to peroxidation and lipid composition in overweight and obese female erythrocytes

The increased generation of reactive oxygen species that occurs in the condition of obesity may be responsible for oxidative injury to erythrocyte membranes, which could lead to a decrease in tissue oxygenation. Therefore, we have looked into the effects of obesity on both indexes of oxidative damage and physical-chemical properties of erythrocyte membranes in 50 overweight or obese [25 < body mass index (BMI) < 33], normotensive, nondiabetic women and 50 age-matched lean healthy women (BMI < 25). In the obese group compared with the lean group, we found that a) the onset of free radical-induced erythrocyte hemolysis and the ratio between reduced and oxidized glutathione were reduced, whereas the rate of free radical-induced damage increased; b) the n-3 fatty acid and the phospholipid contents decreased; c) the ratio between cholesterol and phospholipids increased; and d) the membrane fluidity decreased. These findings suggest an impairment of erythrocyte membrane physical-chemical properties in overweight and obese people as a consequence of oxidative injury that might be part of a pathogenetic mechanism responsible for obesity-related pathologies such as atherosclerosis and hypertension.

Divalent Cations Increase Lipid Order in Erythrocytes and Susceptibility to Secretory Phospholipase A 2

Elevated concentrations of intracellular calcium in erythrocytes increase membrane order and susceptibility to secretory phospholipase A 2. We hypothesize that calcium aids the formation of domains of ordered lipids within erythrocyte membranes by interacting directly with the inner leaflet of the cell membrane. The interface of these domains with regions of more fluid lipids may create an environment with weakened neighbor-neighbor interactions that would facilitate phospholipid migration into the active site of bound secretory phospholipase A 2. This hypothesis was investigated by determining the effects of seven other divalent ions on erythrocyte membrane properties. Changes in membrane order were assessed with steady-state fluorescence spectroscopy and two-photon microscopy with an environment-sensitive probe, laurdan. Each ion increased apparent membrane order in model membranes and in erythrocytes when introduced with an ionophore, suggesting that direct binding to the inner face of the membrane accounts for the effects of calcium on membrane fluidity. Furthermore, the degree to which ions affected membrane properties correlated with the ionic radius and electronegativity of the ions. Lastly, erythrocytes became more susceptible to enzyme hydrolysis in the presence of elevated intracellular levels of nickel and manganese, but not magnesium. These differences appeared related to the ability of the ions to induce a transition in erythrocyte shape.

Modifying effect of Mn(II) amino acid chelate on structural and functional properties of erythrocyte membranes in animals exposed to ionizing radiation.

Modifying effect of Mn(II) amino acid chelate on structural and functional properties of erythrocyte membranes in animals exposed to ionizing radiation.

Changes in mu opioid receptors and rheological properties of erythrocytes among opioid abusers.

Opioids, reported originally to bind to specific receptors in the brain, now also appear to bind to receptors on blood cells. The high prevalence of anemia among chronic opioid users leads us to propose that chronic opiate use results in elevated mu opioid receptor levels on human erythrocytes and that these receptor changes may affect erythrocyte membrane properties. Blood samples from 17 opioid-dependent subjects (based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition or DSM-IV) and 15 drug-free controls were assayed for mu opioid receptors on erythrocytes using a flow cytometry immunoassay. Deformability and the hydration status of erythrocytes were studied by ektacytometry. Data were analyzed by independent t-tests, tests of correlation, chi square and cluster analyses. As expected, the percentage of erythrocytes from opioid-dependent subjects with opioid receptors (opioid receptor levels) was significantly higher (47.4 +/- 38.3%) than controls (22.8 +/- 30.1%) (t = 2.01, df = 30, p < 0.05). Also, the opioid-dependent patients showed a wide variation in the percentage of erythrocytes bearing opioid receptors and data analyses of these patients showed two strongly defined clusters. One subgroup consisted of nine individuals with very high receptor levels (mean = 81.5%) while the other had eight patients with low receptor levels (mean = 9.1%) that were not significantly different than the receptor levels of controls. Ektacytometry of opioid dependent patients with high opioid receptor levels showed changes in rheological parameters of erythrocytes, such as deformability index and cellular hydration. For example, a positive correlation was observed between opioid receptor levels and deformability indices among opioid-dependent patients (r = 0.74, p < 0.005). Our findings indicate that the mu opioid receptor is present on human erythrocytes, although with considerable variation in receptor levels, and that the levels of this receptor are significantly elevated with chronic opioid exposure. Moreover, erythrocytes with high opioid receptor levels from chronic opiate users seem to have high deformability. This study may offer clues to the biological properties of peripheral blood cells that may be mediated by mu opioid receptors and lead to a better understanding of some of the clinical effects of opioid use.

Changes in the Composition, Structure, and Metabolism of Erythrocyte Membranes in Schizophrenia and Other Psychopathologies

Changes in the lipid-protein composition and structural/metabolic properties of erythrocyte membranes were analyzed in 18 patients with heboid paranoia examined in the period of exacerbation of this disease, as well as in 24 patients with mental retardation and in 24 patients with neurotic disorders. The control group included 45 mentally and somatically healthy persons. In our study, we used the following techniques: thin-layer chromatography, fluorochrome assay, measuring of Na+,K+-ATPase activity and level of lipid peroxidation, separation of the membrane proteins by electrophoresis, and transmission electron microscopy. In the erythrocyte membranes of patients with exacerbated heboid paranoia, who obtained no psychopharmacological correction before the examination, we observed clear increases in the relative amounts of cholesterol and lysophosphatidylcholine, drops in the levels of phosphatidylethanolamine and phosphatidylcholine, a rise in the microviscosity of the lipid phase, marked disorganization of the membrane protein spectrum, and a significant decrease in Na+,K+-ATPase activity accompanied by ultrastructural manifestations of damage to the erythrocyte membranes. Comparison of the structural and metabolic properties of erythrocyte membranes in schizophrenic patients with those in patients with exogenous mental retardation and neurotic disorders showed that an overwhelming part of the observed changes in the indices under study were similar in their direction, and intergroup differences were of a quantitative character. These data allow us to postulate that disorganization of the cell membranes in the extracerebral cellular systems in schizophrenia and other mental disorders is, on the one hand, significant and, on the other hand, nonspecific.

In situ assessment of erythrocyte membrane properties during cold storage

Membrane fluidity and overall protein secondary structure of human erythrocytes were studied in situ using Fourier transform infrared spectroscopy (FTIR). Erythrocyte membranes were found to have weakly cooperative phase transitions at 14 degrees C and at 34 degrees C, which were tentatively assigned to the melting of the inner membrane leaflet and the sphingolipid rich outer leaflet, respectively. Cholesterol depletion by methyl-beta-cyclodextrin (MbetaCD) resulted in a large increase in the cooperativity of these transitions, and led to the appearance of another phospholipid transition at 25 degrees C. Multiple, sharp membrane phase transitions were observed after 5 days cold storage (4 degrees C ), which indicated phase separation of the membrane lipids. Using fluorescence microscopy, it was determined that the lipid probe 1,1'-dioctadecyl-3,3,3',3-tetramethyl-indocarbocyanine perchlorate (dil-C18) remained homogeneously distributed in the erythrocyte membrane during cold storage, suggesting that lipid domains were below the resolution limit of the microscope. Using thin layer chromatography, changes in the membrane lipid composition were detected during cold storage. By contrast, assessment of the amide-II band with FTIR showed that the overall protein secondary structure of haemoglobin was stable during cold storage.

Regulation of erythrocyte ghost membrane mechanical stability by chlorpromazine

Chlorpromazine (CPZ), a widely used tranquilizer, is known to induce stomatocytic shape changes in human erythrocytes. However, the effect of CPZ on membrane mechanical properties of erythrocyte membranes has not been documented. In the present study we show that CPZ induces a dose-dependent increase in mechanical stability of erythrocyte ghost membrane. Furthermore, we document that spectrin specifically binds to CPZ intercalated into inside-out vesicles depleted of all peripheral proteins. These findings imply that CPZ-induced mechanical stabilization of the erythrocyte ghost membranes may be mediated by direct binding of spectrin to the bilayer. Membrane active drugs that partition into lipid bilayer can thus induce cytoskeletal protein interactions with the membrane and modulate membrane material properties.

In vitro effects of ozone on human erythrocyte membranes: an EPR study.

The effects of ozone at different concentrations (10, 30, 45 g/m3) on fluidity and thermotropic properties of erythrocyte membranes were investigated by EPR using two spin probes: 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA). The effect of ozone on the erythrocyte membrane fluidity was a dose-dependent process. The ozone at concentration of 10 g/m3 caused rigidization of the membrane while at concentration of 45 g/m3 increased fluidity both on the surface and in the deeper hydrocarbon region of the membrane. Temperature transitions close to the polar heads region (monitored by 5-DSA) were not sensitive to an increase in ozone concentration. In the case of 16-DSA, low temperature thermotropic transition (around 20 degrees C) gradually decreased with the increase of ozone concentration. High temperature transition (around 40 degrees C) significantly differed at the ozone concentration of 10 g/m3 and 45 g/m3, being higher and lower, respectively, as compared to untreated cells. For the ozone concentration of 45 g/m3 the disappearance of the low temperature break and the appearance of two breaks at 37 degrees C and 16 degrees C were observed.

Erythrocyte Aggregation and Erythrocyte Membrane Properties in Type 2 Diabetes mellitus and in Vascular Atherosclerotic Disease

Erythrocyte Aggregation and Erythrocyte Membrane Properties in Type 2 Diabetes mellitus and in Vascular Atherosclerotic Disease -

In vitro effects of sodium fluoride and sodium dichromate on dynamic properties of human erythrocyte membrane

Sodium fluoride (NaF) and sodium dichromate (Na 2Cr 2O 7) are two different toxic compounds which are used as a dental caries prophylactic and as an oxidising agent in various industrial areas, respectively. However, accidental fluoride and chromate poisoning is not a rare occurrence, even death may result from cardiac or respiratory failure. In the present work, alterations produced by NaF, Na 2Cr 2O 7 and temperature changes in the molecular dynamics of the human erythrocyte membrane were studied, in vitro, by the spin-labelling ESR technique. Human intact erythrocyte cells spin labelled with 5- and 16-doxyl stearic acids (5-DSA and 16-DSA) and treated with 40 μM NaF and 5 μM Na 2Cr 2O 7 at 37°C were used to quantify membrane fluidity. This was performed by measuring the changes in the order parameter ( S), correlation time (τ) and phase transition temperature using recorded electron spin resonance (ESR) spectra. Experimental results show that 5 μM Na 2Cr 2O 7 and 40 μM NaF do not produce any significant effects on the order parameter of 5-DSA spin label while they cause appreciable changes in the correlation time of the same label. As for 16-DSA, while Na 2Cr 2O 7 does not produce any measurable effect on the order parameter of this label, NaF does in a certain extent. Although weak, the effects of both compounds on the correlation time of 16-DSA are found to be well above the experimental error limits. Change in temperature was observed to alter significantly S and τ parameters which show biphasic character in the temperature range of 5–50°C. Activation energies of the hydrocarbon chains above and below transition temperatures were also determined for untreated and NaF or Na 2Cr 2O 7 treated erythrocyte cells and the effect of NaF and Na 2Cr 2O 7 on these energies and transition temperatures were discussed.