Erythrocyte Membrane Phospholipid Composition Research Articles

Peculiarities of phospholipiid changes in erythrocyte membranes in parturient women with COVID-19-associated community-acquired pneumonia

Aim. To evaluate the phospholipid composition of erythrocyte membranes in parturient women who had COVID-19-associated community-acquired pneumonia (CAP) in the third trimester.Materials and methods. The material for the study was erythrocytes of peripheral blood of 65 parturient women diagnosed with COVID-19, moderate/severe course, CAP of viral etiology (main group). Patients of the main group, depending on the severity of CAP, were divided into two subgroups: subgroup 1 – moderate course of pneumonia (n=33), subgroup 2 – severe course of pneumonia (n=32). The control group consisted of 35 healthy parturient women. The quantitative composition of phospholipids was studied by two-dimensional thin-layer chromatography according to Kirchner.Results. In subgroup 1, the concentration of phosphatidylethanolamine and phosphatidylcholine in erythrocyte membranes was below the standard values by 38% and 29%, respectively (p<0.001), in subgroup 2, these indicators decreased by 32% and 48%, respectively (p<0.001). At the same time, a significant increase in the concentration of lysophosphatidylcholine was found in patients of subgroup 1 by 92% (p<0.001) and in patients of subgroup 2 by 110% (p<0.001), compared with the group of healthy individuals. In addition, structural changes in the lipid bilayer of erythrocyte membranes under conditions of COVID-19associated CAP were characterized by a pronounced increase in the concentration of minor fractions of phospholipids: phosphatidylserine and phosphatidylinositol in subgroup 1 by 63% and 53%, respectively (p<0.001), in subgroup 2 by 79% and 68%, respectively (p<0.001), compared with similar indicators in the control group.Conclusion. With COVID19-associated CAP in maternity women, structural disorganization of the phospholipid components of erythrocyte membranes is determined, manifested by a decrease in the concentration of phosphatidylethanolamine and phosphatidylcholine with a simultaneous increase in the level of lysophosphatidylcholine, phosphatidylserine and phosphatidylinositol. These disorders increase with increasing severity of pulmonary inflammation. The revealed changes in the lipid spectrum of peripheral blood and the composition of erythrocyte membrane phospholipids in COVID-19-associated CAP indicate the need to develop methods for their correction.

Modification of erythrocyte membrane phospholipid composition in preterm newborns with retinopathy of prematurity: The omegaROP study.

N-3 polyunsaturated fatty acids (PUFAs) may prevent retinal vascular abnormalities observed in oxygen-induced retinopathy, a model of retinopathy of prematurity (ROP). In the OmegaROP prospective cohort study, we showed that preterm infants who will develop ROP accumulate the n-6 PUFA arachidonic acid (ARA) at the expense of the n-3 PUFA docosahexaenoic acid (DHA) in erythrocytes with advancing gestational age (GA). As mice lacking plasmalogens ―That are specific phospholipids considered as reservoirs of n-6 and n-3 PUFAs― Display a ROP-like phenotype, the aim of this study was to determine whether plasmalogens are responsible for the changes observed in subjects from the OmegaROP study. Accordingly, preterm infants aged less than 29 weeks GA were recruited at birth in the Neonatal Intensive Care Unit of University Hospital Dijon, France. Blood was sampled very early after birth to avoid any nutritional influence on its lipid composition. The lipid composition of erythrocytes and the structure of phospholipids including plasmalogens were determined by global lipidomics using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). LC-HRMS data confirmed our previous observations by showing a negative association between the erythrocyte content in phospholipid esterified to n-6 PUFAs and GA in infants without ROP (rho = −0.485, p = 0.013 and rho = −0.477, p = 0.015 for ethanolamine and choline total phospholipids, respectively). Phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) species with ARA, namely PtdCho16:0/20:4 (rho = −0.511, p < 0.01) and PtdEtn18:1/20:4 (rho = −0.479, p = 0.015), were the major contributors to the relationship observed. On the contrary, preterm infants developing ROP displayed negative association between PtdEtn species with n-3 PUFAs and GA (rho = −0.380, p = 0.034). They were also characterized by a positive association between GA and the ratio of ethanolamine plasmalogens (PlsEtn) with n-6 PUFA to PlsEtn with n-3 PUFAs (rho = 0.420, p = 0.029), as well as the ratio of PlsEtn with ARA to PlsEtn with DHA (rho = 0.843, p = 0.011). Altogether, these data confirm the potential accumulation of n-6 PUFAs with advancing GA in erythrocytes of infants developing ROP. These changes may be partly due to plasmalogens.

Decreases of ethanolamine plasmalogen and phosphatidylcholine in erythrocyte are a common phenomenon in Alzheimer’s, Parkinson’s, and coronary artery diseases

Decreased plasma levels of plasmalogens in neurodegenerative diseases have been watched with interest. We previously reported the decreases of erythrocyte ethanolamine plasmalogen (PlsPE) of blood not only in Alzheimer’s disease (AD) and Parkinson’s disease (PD), but also in coronary artery disease (CAD). In the present study, by using the same high-performance liquid chromatography (HPLC) method, we investigated the pattern of changes in the phospholipid composition of erythrocyte membrane in AD, PD and CAD compared with healthy individuals. The common patten of changes among them was as follows: The decrease of erythrocyte PlsPE was accompanied by a decrease of phosphatidylcholine although phosphatidylethanolamine remained unchanged. The decreases of PlsPE and phosphatidylcholine were replaced by an increase of sphingomyelin (SM) in the total phospholipids. The dissociated change between PlsPE and phosphatidylethanolamine (PE) may be caused by the differences in molecular structure or in location in the cell membrane. Such special changes provide another piece of biochemical evidence that these different diseases are caused by identical pathological mechanism, suggesting potential biomarkers for these chronic diseases due to aging.

Erythrocyte deformability and aggregation in morbidly obese women undergoing laparoscopic gastric bypass surgery and effects of oral omega-3 fatty acid supplementation.

An adequate erythrocyte function is vital for tissue oxygenation and wound healing. The erythrocyte membrane phospholipid composition plays an important role in erythrocyte function and administration of omega-3 fatty acids may provide a means to improve it. To investigate peri-operative erythrocyte function and effects of oral omega-3 fatty acids in morbidly obese women undergoing gastric bypass surgeryMETHODS:Fifty-six morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery were randomized between a low calorie diet (LCD) during 2 weeks or oral omega-3 poly-unsaturated fatty acids (n-3 PUFAs) and a normal diet during 4 weeks. Peri-operative blood samples were analyzed with the Lorrca MaxSIS Ektacytometer for erythrocyte deformability and aggregability. There were no significant differences in erythrocyte function between the groups at any time point. Only erythrocyte aggregability parameters were affected by surgery. At six month follow-up, aggregation index (AI) and cholesterol, glucose and insulin were significantly improved. In this study, oral Omega-3 supplementation did not affect erythrocyte function compared to a LCD. Six months after surgery a significant improvement in AI and metabolic parameters was observed in both groups, contributing to a reduction in the risk at thromboembolic and cardiovascular complications.

Erythrocyte deformability and aggregability in patients undergoing colon cancer surgery and effects of two infusions with omega-3 fatty acids.

An adequate erythrocyte function is vital for tissue oxygenation and wound healing. The erythrocyte membrane phospholipid composition plays an important role in erythrocyte function and administration of omega-3 fatty acids may provide a means to improve it. To investigate peri-operative erythrocyte function and effects of omega-3 fatty acidsMETHODS:Forty-four patients undergoing elective laparoscopic colon resection for non-metastasized cancer were randomized between intravenous omega-3 poly-unsaturated fatty acids (n-3 PUFAs) or placebo (saline). Peri-operative blood samples were analyzed with a Lorrca MaxSIS Ektacytometer and erythrocyte membrane phospholipids were determined with gas chromatography. Patient and operation characteristics were equal between groups. There was a significant increase in erythrocyte membrane eicosapentaenoic acid (EPA) but not docosahexaenoic acid (DHA) in the n-PUFA group. There were no significant differences in erythrocyte deformability but the aggregation index (AI) was significantly lower and the aggregation half time (T½) was significantly higher in the n-3 PUFA group. This study confirms rapid changes in erythrocyte membrane phospholipid composition after administration of intravenous n-3 PUFAs. Erythrocyte deformability parameters were not affected but erythrocyte aggregability was decreased in the n-3 PUFA group. Further investigation is necessary to gain more insights in the effects of n-3 PUFA and the postoperative inflammatory response on erythrocyte function.

Changes in Phospholipid Composition of Erythrocyte Membrane in Alzheimer’s Disease

Background: There are several reports indicating a decrease of ethanolamine plasmalogen (pl-PE) in brain tissues and in serum of patients with Alzheimer’s disease (AD). The present study aimed to examine the composition of erythrocyte phospholipids including pl-PE in patients with AD. Method: A high-performance liquid chromatography (HPLC) method that can separate intact plasmalogens and all other phospholipid classes by a single chromatographic run was used. Results: The ratios of pl-PE, phosphatidylethanolamine (PE) and phosphatidylserine (PS) to sphingomyelin were low as compared to those of the age-matched controls. Conclusion: These changes in erythrocyte phospholipids may reflect changes induced by oxidative stress, indicating the presence of high oxidative stress in the peripheral blood of AD patients.

Update on Omega-3 Polyunsaturated Fatty Acids in Early-Stage Psychotic Disorders

Polyunsaturated fatty acids (PUFAs) are the major constituents of cell membrane phospholipids. As such, they have multiple important biological roles, including in receptor binding, neurotransmission, signal transduction, and eicosanoid synthesis. A growing body of studies suggests significant reductions in PUFA levels in people with schizophrenia (Berger et al, 2006). Concordant with these findings, fatty acids, particularly the omega-3 PUFA, may have a beneficial role in the treatment of first-episode schizophrenia, and in the prevention of schizophrenia, while results in chronic schizophrenia have been mixed (Peet, 2008). We have recently tested whether supplementation with omega-3 PUFA could reduce the rate of transition to first-episode psychosis in an ultra-high risk (UHR) cohort. In our study, we randomized 81 individuals aged 13–25 years to 12 weeks of either 1.2 g/day of omega-3 PUFA or placebo, followed by a 40-week monitoring period. In all, 2 of 41 (4.9%) of those receiving the active agent transitioned to psychosis, compared with 11 of 40 (27.5%) in the placebo group, a statistically significant difference (Amminger et al, 2010). While PUFAs have been investigated in schizophrenia, their role in the onset of psychotic symptoms is unclear. Therefore, we examined the relationship between omega-3 PUFA (ie, alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)) levels in erythrocyte membrane phosphatidylethanolamine and measures of psychopathology in our UHR cohort at baseline. Erythrocyte membrane phospholipid composition closely reflects that of neuronal membranes, and provides an easily accessible indicator of brain phospholipids. While ALA, EPA, and DHA did not correlate significantly with any symptom measure, low levels of DPA and the summary score of all assessed omega-3 fatty acids (ie, ALA, EPA, DPA, and DHA) correlated with more severe negative symptoms. These correlations remained significant after adjustment for potential confounders (ie, age, sex, and nicotine use). Reduced DPA has been previously reported in neuroleptic-naive first-episode schizophrenia patients (Reddy et al, 2004). Given our intervention study provided support for the ‘dose–response' criterion (McNamara, 2011), as an increase in erythrocyte omega-3 PUFA levels reduced the rate of transition to psychosis and correlated with functional improvement, we tested if the subjects with the lowest erythrocyte omega-3 levels at baseline were at higher risk for transitioning to psychosis. To eliminate treatment effects, we only investigated those participants who had received placebo. Cox regression analyses with adjustment for age, sex, and nicotine use indicated that no single omega-3 PUFA or their summary score predicted conversion to psychosis. Following studies reporting lower levels of arachidonic acid (AA) and nervonic acid (NA), as well as DHA, in people with schizophrenia (Assies et al, 2001), we also examined if these fatty acids predicted transition to psychosis. While AA was not found to be predictive, low NA levels at baseline significantly predicted transition to psychosis (Amminger et al, submitted). As NA is a major constituent of the myelin sheath, low levels of NA could reflect suboptimal myelination in those UHR individuals who develop a psychotic disorder. The finding is consistent with the well-established finding of white matter abnormalities in schizophrenia (Ellison-Wright and Bullmore, 2009). Notably, the observation that supplementation with omega-3 PUFAs may prevent transition to psychosis suggests that omega-3 fatty acids may offset the risk conferred by decreased levels of NA. A randomized controlled multicenter phase III clinical trial of omega-3 PUFA is now underway to replicate the findings (Australian New Zealand Clinical Trials Registry - ACTRN12608000475347).

Clinical and basal aspects of anemia during antiviral therapy for hepatitis C

Background and Rationale. Anemia is a major side effect of combination therapy for chronic hepatitis C. In this study, severity, potential risk factors for and potential underlying mechanisms of anemia were evaluated.Patients and methods. 44 chronic hepatitis C patients on interferon-ribavirin treatment were included. Anemia-related parameters were measured before and during treatment. Potential changes in membrane phospholipids composition of erythrocytes of patients on anti-viral treatment and potentially increased erythrocyte susceptibility to osmotic or bile salt induced stress were explored.Results. Anemia was almost universal during treatment, with evidence of hemolysis. Decrease of Hb after six months of therapy was 2.1 ± O.I mmol/L (range -0.6-4.1). Higher pre-treatment Hb, highest ribavirin dose (1S-17.S mg/kg) and lower pre-treatment platelet level were independent risk factors for decrease of Hb. Serum erythropoietin levels increased during treatment with negative correlation to Hb levels at week 12 (r = -0.70, p = 0.002) and 24 (r = -0.72, p = 0.002). Erythrocyte membrane phospholipid composition did not differ between anemic patients and healthy controls. Also, resistance to osmotic or bile salt induced stress was normal in anemic patients. Phosphatidylserine exposure at the outer membrane leaflet did not change upon 24 hrs ex vivo incubation with pharmacological ribavirin concentration.Conclusions. Anemia is almost universal during anti-HCV treatment. The extent of anemia correlates with pre-treatment levels of thrombocytes and Hb and with high ribavirin dosing. Although we found hemolysis as contributing factor, our data do not indicate that altered membrane phospholipids composition is an important factor in pathogenesis of anemia.

Phospholipid composition of erythrocyte membrane under conditions of postmyocardial infarction cardiosclerosis

Changes in phospholipid composition of the erythrocyte membranes have been studied in experimental postmyocardial infarction cardiosclerosis. Erythrocyte membranes from animals with cardiosclerosis formed after experimantal occlusions of coronary arteries were characterized by significant decrease of a minor phospholipid, phosphatydylinositol (by more than 40%) and the increase of the major phospholipid, phosphatydylethanolamine. There was high content of lipid peroxidation products, malondialdehyde and conjugated dienes and the decrease in the activity of antioxidant enzymes, catalase and superoxide dismutase in blood serum of these animals. We have concluded the formation of postmyocardial infarction cardiosclerosis is accompanied by the increase of free radical reactions. This causes changes in phospholipid composition of cell membranes and the decrease of compensatory capacities of the enzymatic antioxidant system. These changes form a metabolic background, [corrected] which can influence cardiac remodelling properties.

Erythrocyte Membrane Phospholipid Composition as a Biomarker of Dietary Fat

Background/Aims: In a cross-sectional study, we investigated the relationship between erythrocyte membrane phospholipid fatty acid composition and dietary fat; we also investigated roles of menopausal status, age, body mass index (BMI) and waist-to-hip ratio (WHR) in interindividual variation of the biomarker. Methods: Study participants were 204 women, aged 39–65 years, drawn from the ORDET cohort and selected as controls in a study of breast cancer. Membrane composition was assessed using capillary gas chromatography. Dietary fat composition was evaluated using a food frequency questionnaire. Results: In pre- and postmenopausal women, erythrocyte membrane phospholipid levels of linoleic acid, oleic acid, and mono-unsaturated fatty acids were significantly associated with corresponding dietary measures (partial correlation coefficients: 0.23 and 0.39; 0.45 and 0.47; 0.40 and 0.48; respectively, in pre- and postmenopausal women). Among postmenopausal women, membrane poly-unsaturated fatty acids were correlated with the corresponding dietary measure (r = 0.39, p < 0.001). Membrane eicosapentanoic and docosahexanoic acid levels were significantly correlated with intake of fish/shell fish : r = 0.21 and r = 0.43 (premenopausal), and r = 0.41 and r = 0.44 (postmenopausal). Age, BMI and WHR had independent effects on membrane lipid composition. Age was associated with delta-6 desaturase activity in postmenopausal women (r = 0.25, p < 0.05). BMI was negatively associated with delta-9 desaturase activity in both pre- and postmenopausal women (r = –0.29, p = 0.01 and r = –0.22, p < 0.01, respectively). WHR was negatively associated with delta-5 desaturase activity in pre-menopausal women (r = –024, p < 0.05). Conclusions: Erythrocyte membrane levels of some specific fatty acids can be used as biomarkers of these fatty acids as proportions of dietary fat.

Photosensitizing Effect of Some Nonsteroidal Antiinflammatory Drugs on Natural and Artificial Membranes: Dependence on Phospholipid Composition

Previous studies have clarified the molecular mechanism of photosensitization on red blood cell membranes induced by some drugs belonging to the class of nonsteroidal antiinflammatory drugs: ketoprofen, naproxen, and diflunisal. This process involves the participation of photodegradation products, free radicals, and reactive oxygen species. The aim of the present paper is to investigate the photohemolytic process using red blood cells of mammalian species, with different membrane phospholipid compositions. Human and bovine red blood cell membranes were selectively enriched with phosphatidylcholine and sphingomyelin. For this purpose, a new approach for phospholipid investigation was undertaken. Moreover, the phototoxic effect was tested with liposomes at different phospholipid compositions. A structure-function relationship between the erythrocyte membrane phospholipid composition and the photohemolytic process induced by the sensitizers can be proposed. Indeed, the different contents of the photoperoxidable double bond and the variable architecture of the membrane bilayer, due to the different phosphatidylcholine and sphingomyelin contents, strongly influence the resistance of the cell to an osmotic shock induced by photogenerated transient species or by the lytic activity of drug photoproducts. The higher content of sphingomyelin, its asymmetric disposition at the outer surface of membrane bilayers, the high level of saturated acyl fatty chains, and the presence of photoperoxidable trans double bonds in the hydrophilic region greatly decrease the fluidity of bilayers and enhance the resistance of the membrane to phototoxic damage. On the other hand, an increase in the content of phosphatidylcholine, which is rich in species with unsaturated acyl fatty chains, decreases the membrane resistance, because these latter can be easily oxidized by drug-photogenerated reactive oxygen species.

Significantly reduced docosahexaenoic and docosapentaenoic acid concentrations in erythrocyte membranes from schizophrenic patients compared with a carefully matched control group

Background: Fatty acid research in schizophrenia has demonstrated an altered cell membrane phospholipid metabolism. Erythrocyte membrane phospholipid composition closest reflects that of neuronal membranes. Methods: (Poly)(un)saturated fatty acid concentrations were measured in the erythrocyte membranes of 19, consecutively admitted, medicated young schizophrenic patients and then compared with matched control subjects. Psychiatric symptomatology was rated with the Positive and Negative Symptom Scale and Montgomery-Åsberg Depression Rating Scale. Because diet, hormones, and cannabis influence fatty acid metabolism, we included these factors in our study. Results: The most distinctive findings concerned the ω-3 series: C22:5ω-3, C22:6ω-3 (docosahexaenoic acid), and the sum of ω-3 fatty acids were significantly decreased. Interestingly, C20:4ω-6 (arachidonic acid) was not lowered. In the ω-9 series, higher levels of C22:1ω-9 and lower levels its elongation product, C24:1ω-9 (nervonic acid), were found. Interestingly, the other arm of the desaturation–elongation sequence of C18:1ω-9, C20:3ω-9, was lower in patients. The total ω-9 fatty acid levels were also lower in patients. Conclusions: Significant differences in erythrocyte fatty acid composition were found. The differences were not due to diet or hormonal status and could not be explained by the medication or cannabis use. No consistent pattern emerged from the different fatty acid abnormalities and the clinical symptom scores.

Phosphatidylcholine formation is the predominant lipid biosynthetic event in the hemoparasite Babesia bovis

This work examines the lipid composition and metabolism of bovine red blood cells infected by apicomplexan Babesia parasites, organisms closely related to Plasmodium sp . We found that erythrocytes infected with Babesia bovis (i-RBC) accumulate lipids and show striking increases in phosphatidylcholine, phosphatidic acid, diacylglycerol and cholesteryl esters as compared to uninfected erythrocytes cultured under the same conditions (n-RBC). A similar pattern was observed in cultures of erythrocytes infected with Babesia bigemina. The lipid profile of purified B. bovis merozoites showed that phosphatidylcholine is the most abundant phospholipid in this parasite (31.8%±2.8 of total phospholipid), markedly differing from bovine n-RBC, in which it is only a minor component (4.8%±0.6). B. bovis cultures incorporate radiolabeled choline into complex lipids, especially phosphatidylcholine, with minor amounts recovered in sphingomyelin and lysophosphatidylcholine. When [ 14C] stearate was used as precursor, the labeling pattern again gave the highest incorporation into phosphatidylcholine, with lesser incorporation in sphingomyelin, phosphatidylinositol, phosphatidylethanolamine and phosphatidic acid. Diacylglycerol and small amounts of cholesteryl esters were the only labeled neutral lipids found. B. bovis also incorporates [ 3H] myo-inositol into phosphatidylinositol. Parallel incubations with n-RBC as a control yielded no incorporation into either polar or neutral lipids with any precursor. These results indicate that the lipid changes observed in i-RBC can be explained on the basis of the lipid biosynthetic activities of the babesial parasite. Gas chromatography-mass spectrometry (GC-MS) analysis of fatty acid methyl esters from phospholipids of i-RBC and n-RBC showed the same qualitative composition in both. However, i-RBC had higher ratios of saturated to unsaturated fatty acids and B. bovis cultures did not desaturate [ 14C] stearate. Cholesterol was the only sterol detected by GC-MS. Phospholipase A 2 treatment of i-RBC and n-RBC revealed no enhanced hemolytic effects in i-RBC, suggesting that the erythrocyte membrane phospholipid composition is essentially unaltered by the parasite. Labeling of i-RBC or n-RBC with [ 125I] Bolton-Hunter resulted in an enhanced phosphatidylserine labeling in i-RBC. This study provides the first data on B. bovis lipid constitution and biosynthesis. They show that phosphatidylcholine formation is the main biosynthetic process in these cells. The striking differences in the contents of phosphatidylcholine between host erythrocytes and the parasite suggests that it may be a useful target for both chemotherapy and immunoprophylaxis against bovine babesiosis.

Phospholipid composition of the mammalian red cell membrane can be rationalized by a superlattice model.

Although the phospholipid composition of the erythrocyte membrane has been studied extensively, it remains an enigma as to how the observed composition arises and is maintained. We show here that the phospholipid composition of the human erythrocyte membrane as a whole, as well as the composition of its individual leaflets, is closely predicted by a model proposing that phospholipid head groups tend to adopt regular, superlattice-like lateral distributions. The phospholipid composition of the erythrocyte membrane from most other mammalian species, as well as of the platelet plasma membrane, also agrees closely with the predictions of the superlattice model. Statistical analyses indicate that the agreement between the observed and predicted compositions is highly significant, thus suggesting that head group superlattices may indeed play a central role in the maintenance of the phospholipid composition of the erythrocyte membrane.

Evidence of oxidative stress in erythrocyte phospholipid composition in the pathogenesis of familial Mediterranean fever (periodical disease).

Familial Mediterranean fever (FMF) is a genetically linked disorder common amongst races of the Eastern Mediterranean region. Typical symptoms include episodic pain syndrome extending throughout the chest or abdomen associated with histopathological signs of amyloidosis of the kidney. To investigate possible connections between the aseptic inflammation that occurs during pain crises and cell membrane structural and functional integrity in patients with FMF. Oxidative stress parameters in 42 patients in remission and during a pain crisis were compared with 21 normal subjects. The patient group had significantly greater concentrations of chemiluminescent and thiobarbituric acid-reactive substances in the blood plasma and lower concentrations of alpha-tocopherol than the control group while in remission; these changes were exacerbated during pain crises. Analyses of the phospholipid composition of erythrocyte membranes showed significant increases in amounts of acidic phospholipids (phosphatidic acid, monophosphatidylinositol and cardiolipin) and lysophosphatidylcholine compared with healthy subjects. The pattern of differences in membrane phospholipid composition was consistent with increased oxidative stress in patients with FMF.

Phospholipid composition of erythrocyte membranes and plasma of mammalian blood including australian marsupials; Quantitative 31P NMR Analysis using detergent

The phospholipid classes of erythrocyte membranes and plasma from several domestic animals and marsupials were quantified by 31P NMR using detergents. Washed erythrocyte samples were thoroughly haemolysed by tip-sonication and dissolved in sodium cholate; plasma samples were dissolved in Triton X-100. The species studied were: common wombat ( Vombatus ursinus), black-striped wallaby ( Macropus dorsalis), bandicoot ( Isoodon macrocarpus), Eastern grey kangaroo ( Macropus giganteus), Tammar wallaby ( Macropus eugenii), sheep (Ovis aries), goat ( Capra hircus), cattle ( Bos taurus), horse ( Equus caballus), dog ( Canus familiaris) and rabbit ( Orytolagus caniculus). There were considerable species variations in the relative abundance of erythrocyte and plasma phospholipid classes. The variations may be attributed to the habitats and diets of the animals as well as to their phylogenetic differences.

Erythrocyte membrane phospholipids in psychotic patients

Thin layer chromatography and laser densitometry were used to examine erythrocyte membrane phospholipid composition in 13 medication-free patients with schizophrenia or schizoaffective disorder and 11 healthy control subjects. The patient group had significantly decreased levels of phosphatidyl-ethanolamine and a significant increase in sphingomyelin. The patient group also showed a trend toward decreased levels of phosphatidylinositol bisphosphate. Levels of phosphatidylcholine and lysophosphatidylcholine did not significantly differ between groups. There were no significant effects of age, body mass index, or gender on any of the phospholipid parameters. The observed alterations may point to abnormalities in key membrane-related functions, including signal transduction and ion transport.

Changes in erythrocyte membrane phospholipid composition induced by physical training and physical exercise.

The effects were investigated of physical training and exercise on lipids of the erythrocyte membrane of healthy students. Membrane cholesterol and phospholipids were analysed simultaneously by thin-layer chromatography with a flame ionization detector and the fatty acid composition was determined by gas chromatography. Physically trained students had similar physical characteristics to control students but a significantly higher aerobic capacity, estimated as the maximal oxygen uptake and anaerobic threshold. Of the phospholipids examined, only the content of membrane phosphatidylserine was significantly lower in the trained group. Fatty acid analysis showed that the amount of docosahexaenoic acid in membrane phosphatidylserine was lower in the trained group. There was no significant difference between the fatty acid compositions of membrane phosphatidylcholine in the two groups. Maximal exercise decreased membrane phosphatidylserine in the control group but not in the trained group. It also significantly decreased the relative amounts of unsaturated fatty acids in both phosphatidylcholine and phosphatidylserine in the untrained group. Maximal oxygen uptake was negatively correlated with the amount of erythrocyte membrane phosphatidylserine. These results would indicate that both physical training and acute exercise decrease phosphatidylserine and polyunsaturated fatty acids in erythrocyte membranes, possibly due to lipid peroxidation, suggesting limited enhancement of erythrocyte defense mechanisms in adaptation to chronic oxidative stress.

Does repeated exposure to fenitrothion alter phospholipid composition of erythrocyte membrane?

Sir, Erythrocytes have acetylcholinesterase (AchE), and its activity is often used as an indicator of intoxication with cholinesterase inhibitors. The physiological function(s) of AchE in erythrocytes, however, have not been clarified. The enzyme is entirely membrane bound and located in the outer side of the membrane (see Igisu et al. 1981). On the other hand, the outer leaflet of the erythrocyte membrane is rich in choline-containing phospholipids, i.e., phosphatidylcholine and sphingomyelin (Rothman and Lenard 1977). Hence, one may speculate that AchE might play a role in the metabolism of phospholipids of the membrane, especially those containing choline. Furthermore, in the brain, cholinergic activity and phosphatidylcholine content appears related (Buyukuysal and Wurtman 1990). We therefore examined whether or not repeated exposure to a potent inhibitor of cholinesterase (fenitrothion) affects phospholipid composition of erythrocyte membrane. Male Wistar rats weighing 150-190 g were used. The animals were exposed to fenitrothion (Sumithion) powder for 2 h a day, 5 times a week for 4 -6 weeks. The fenitrothion powder was generated by an apparatus which can produce powder with a fairly constant concentration over a long period (Tanaka and Akiyama 1984). The exposure concentration, aerodynamic median diameter of the powder, and geometric standard deviation were 12.9+ 17.9 (mg/m3, mean _+ SD), 4.9 Bm, and 2.3, respectively. Three hours after the final exposure, blood was obtained by cardiac puncture under ether anesthesia. Preparation of the erythrocyte membrane and measurement of AchE activity were done as described previously (Igisu et al. 1981 ). Lipids were extracted by the method of Folch et al. (1957) and partitioned with water. Lower-phase lipid was applied to a high performance thin-layer chromatogram (HPTLC) plate (Merck 5641) and developed in a mixture of chloroform-methanol-water (65 : 25 : 4, v/v/v). After visualization by spraying cupric acetate and heating (Fewster et al. 1969), the plate was scanned by a Shimadzu Fig. 1. Thin-layer chromatograms of lipids of erythrocyte membrane from rats of control (1), 4-week exposure (2) and 6-week exposure to fenitrothion (3). Spots of cholesterol (Ch), ethanolamine phospholipids (E), phosphatidylcholine (Pc), serine phospholipid (+ phosphatidylinositol) (S) and sphingomyelin (Sp) are seen

High-performance liquid chromatography determination of erythrocyte membrane phospholipid composition in several animal species

SUMMARY High-performance liquid chromatography (hplc) was used to determine the phospholipid (pl) composition of ovine, equine, bovine, porcine, and canine RBC membranes. Procedural modifications of established techniques provided for separation of 7 pl within a 15- to 20-minute sample run. Significant (P &lt; 0.05) differences were detected in rbc membrane pl composition among the various species. The concern for physiologic properties associated with hemolysis and/or sedimentation rate must include evaluation of differences in the pl bilayer structure.