Red Blood Cell Membrane Lipid Research Articles

Yet more evidence that non-aqueous myelin lipids can be directly imaged with ultrashort echo time (UTE) MRI on a clinical 3T scanner: a lyophilized red blood cell membrane lipid study

Direct imaging of semi-solid lipids, such as myelin, is of great interest as a noninvasive biomarker of neurodegenerative diseases. Yet, the short T2 relaxation times of semi-solid lipid protons hamper direct detection through conventional magnetic resonance imaging (MRI) pulse sequences. In this study, we examined whether a three-dimensional ultrashort echo time (3D UTE) sequence can directly acquire signals from membrane lipids. Membrane lipids from red blood cells (RBC) were collected from commercially available blood as a general model of the myelin lipid bilayer and subjected to D2O exchange and freeze-drying for complete water removal. Sufficiently high MR signals were detected with the 3D UTE sequence, which showed an ultrashort T2* of ∼77–271 µs and a short T1 of ∼189 ms for semi-solid RBC membrane lipids. These measurements can guide designing UTE-based sequences for direct in vivo imaging of membrane lipids.

Bisphenol S remodels red blood cell membrane lipids by altering plasma lipid levels, causing the risk of venous thrombosis in SD rats and zebrafish embryos

Bisphenol S (BPS) is a raw material that is used extensively in various manufacturing processes but possesses a high detection rate in human red blood cells (RBCs). Accordingly, BPS is a potential toxicant in disturbing the function of RBCs and causing RBC-related diseases. To date, the effects and mechanisms of BPS-induced RBC-related diseases have not been elucidated. Here, using different models, including rats, zebrafish embryos and RBCs, the underlying mechanism of RBC-related diseases induced by BPS was explored. The accumulation of BPS in tissue was colon > kidney > liver > plasma > testicle > heart > brain in SD rats orally administered BPS (10 and 50 mg/kg bw/day) for 32 days, which was similar in both 10 mg/kg bw/day and 50 mg/kg bw/day group. Rats given BPS orally developed hyperlipidemia and increased RBC membrane cholesterol, as well as changes in RBC morphology and function. Moreover, BPS at the concentrations measured in rats plasma caused oxidative stress and phosphatidylserine exposure in vitro RBCs. These combined factors led to RBC aggregation in blood and an increasing in the number of RBCs in the blood vessels of the liver in rats. The dynamic visual observation of RBCs in vein vessels of zebrafish embryos exposed to BPS at 0, 1, 10 and 100 μg/L further found that the flow of RBCs in the tail vein is slow or even immobile, posing the risk of venous thrombosis. The present study provides new insight into the links between environmental pollutants and venous thrombosis.

Red blood cells from patients with sitosterolemia exhibit impaired membrane lipid composition and distribution and decreased deformability

Sitosterolemia is a metabolic disorder leading to excessive accumulation of phytosterols. Hemolytic stomatocytosis and macrothrombocytopenia are part of the clinical picture. However, the impact of phytosterols on red blood cell (RBC) deformability, membrane lipid composition and distribution and the efficiency of the reference treatment, Ezetimibe, are largely unknown. This study addresses these issues using RBCs from three patients with sitosterolemia and healthy RBCs exposed to β-sitosterol. Patients presented an increased proportion of stomatocytes, decreased RBC deformability and increased RBC hydration and osmotic fragility compared to healthy donors. At the membrane level, patient RBCs showed (i) very high content in β-sitosterols, (ii) increased proportions of saturated fatty acids and polyunsaturated fatty acid species with long and unsaturated carbon chains, and (iii) decreased content in phosphatidylethanolamine species. These lipid changes were accompanied by an almost complete abrogation of cholesterol-enriched domains, which could result from: (i) the reduced phosphatidylethanolamine content which positively correlated with domain abundance; and (ii) the fatty acid modifications and increased phytosterol content, both compatible with higher membrane stiffness. The role of β-sitosterol was supported by comparable changes in RBC morphology and cholesterol-enriched domains upon β-sitosterol integration at the healthy RBC membrane. Finally, Ezetimibe treatment combined with a sterol restricted diet lowered phytosterols and improved anemia and RBC deformability and hydration. However, this treatment had no or limited effect on RBC morphology and cholesterol-enriched domain abundance. This study reveals for the first time that phytosterols affect RBC membrane lipid composition and distribution but also RBC morphology, hydration, deformability and fragility.

A multi-marker integrative analysis reveals benefits and risks of bariatric surgery

Bariatric surgery (BS) is an effective intervention for severe obesity and associated comorbidities. Although several studies have addressed the clinical and metabolic effects of BS, an integrative analysis of the complex body response to surgery is still lacking. We conducted a longitudinal data study with 36 patients with severe obesity who were tested before, 6 and 12 months after restrictive BS for more than one hundred blood biomarkers, including clinical, oxidative stress and metabolic markers, peptide mediators and red blood cell membrane lipids. By using a synthetic data-driven modeling based on principal component and correlation analyses, we provided evidence that, besides the early, well-known glucose metabolism- and weight loss-associated beneficial effects of BS, a tardive, weight-independent increase of the hepatic cholesterol metabolism occurs that is associated with potentially detrimental inflammatory and metabolic effects. Canonical correlation analysis indicated that oxidative stress is the most predictive feature of the BS-induced changes of both glucose and lipids metabolism. Our results show the power of multi-level correlation analysis to uncover the network of biological pathways affected by BS. This approach highlighted potential health risks of restrictive BS that are disregarded with the current practice to use weight loss as surrogate of BS success.

Consumption of Farmed Fish, Fed with an Olive-Pomace Enriched Diet, and Its Effect on the Inflammatory, Redox, and Platelet-Activating Factor Enzyme Profile of Apparently Healthy Adults: A Double-Blind Randomized Crossover Trial.

A fish-rich diet has a beneficial effect on cardiovascular health. The platelet activating factor (PAF) is involved in the development of atherosclerosis, and in vitro results support the regulating action of bioactive nutrients on PAF metabolism. The purpose of this study is to examine whether the consumption of farmed fish fed with an olive-pomace enriched diet (EF) affects PAF metabolism and the markers of inflammation and oxidative stress compared to the consumption of conventionally fed farmed fish (CF). Thirty apparently healthy adults completed a randomized double-blind crossover trial, during which they consumed both CF and EF twice a week for 8 weeks with a six-week washout period in between. The activities of PAF acetylhydrolase (PAF-AH), lysoPAF acetyltransferase (lysoPAF-AT), DTT-insensitive CDP-choline: 1-alkyl-2-acetyl-sn-glycerol-choline-phosphotransferase (PAF-CPT) in leukocytes, and lipoprotein-associated phospholipase A2 (LpPLA2) in serum were determined. The quantities of interleukin-6 (IL-6), high sensitivity C-reactive protein (hsCRP), oxidized LDL (ox-LDL), thiobarbituric acid-reactive substances (TBARS), and glutathione peroxidase (GPx), as well as the serum oxidation, were also determined. Both types of fish exerted similar effects as there were no statistically significant differences between the two interventions except for an elevated PAF-CPT and reduced arachidonic acid (AA) in the red blood cell (RBC) membrane lipids after the EF intake.

Acute Cycling Exercise Induces Changes in Red Blood Cell Deformability and Membrane Lipid Remodeling.

Here we describe the effects of a controlled, 30 min, high-intensity cycling test on blood rheology and the metabolic profiles of red blood cells (RBCs) and plasma from well-trained males. RBCs demonstrated decreased deformability and trended toward increased generation of microparticles after the test. Meanwhile, metabolomics and lipidomics highlighted oxidative stress and activation of membrane lipid remodeling mechanisms in order to cope with altered properties of circulation resulting from physical exertion during the cycling test. Of note, intermediates from coenzyme A (CoA) synthesis for conjugation to fatty acyl chains, in parallel with reversible conversion of carnitine and acylcarnitines, emerged as metabolites that significantly correlate with RBC deformability and the generation of microparticles during exercise. Taken together, we propose that RBC membrane remodeling and repair plays an active role in the physiologic response to exercise by altering RBC properties.

Microsphere: a promising approach for drug delivery

This work was carried out to show the effects of phenylhydrazine (PHZ) induced anaemic condition. Anaemic condition is defined as reduction in red blood cells (RBC) than normal number of red blood cells. The anti-anaemic activity can be studied using the changes in haematological parameters (PCV, RBC & Haemoglobin) influenced by PHZ [(40mg/kg p.o.)] in rats. PHZ, a potent chemical that causes different effects on different tissues at several levels. Administration of PHZ causes haemolytic anaemia, genotoxic effects and rose in iron absorption in spleen, liver and duodenum & causes change in iron metabolism. PHZ acts by activating immune response which triggers phagocytosis and also interfere with the binding of erythropoietin (EPO) receptors and further JAK-STAT pathway. PHZ also causes genotoxic effect by forming single strand DNA damage. In view of lipid peroxidation along with the formation of Thiobarbituric acid (TBA)-reactive malonyldialdehyde, it is recommend that PHZ induces anaemia as an outcome of peroxidation of RBC membrane lipids and this effect may be a upshot of the autoxidation of the drug and the interaction of membrane lipids and oxygen radicals

The effect of dietary carbohydrates and polyunsaturated fatty acids on red blood cell membrane lipid profile in a cohort of cancer patients

The effect of dietary carbohydrates and polyunsaturated fatty acids on red blood cell membrane lipid profile in a cohort of cancer patients

Взаємозв'язок між дозою тривалого активатора рецепторів еритропоетину та оксидативним стресом у хворих, які лікуються методом гемодіалізу

Наукові дані щодо дозозалежного впливу тривалого активатора рецепторів еритропоетину (ТАРЕ) на показники оксидативного стресу та перекисного окислення ліпідів мембран еритроцитів у хворих на хронічну хворобу нирок V, які лікуються гемодіалізом (ГД), є обмеженими.
 Метою нашої роботи було оцінити взаємозв’язок між застосованою дозою ТАРЕ та інтенсивністю оксидативних процесів у ГД пацієнтів. 
 Матеріал та методи. 38 ГД пацієнтів були включені до одномоментного обсерваційного дослідження. Протокол дослідження був схвалений локальною етичною комісією ДУ «Інститут нефрології НАМН України». Усі пацієнти надали письму інформовану згоду на участь у досліджені. Пацієнти були стратифіковані за квартилями (≤ 25% та ≥ 75%) відповідно до середньої дози ТАРЕ і розподілені наступним чином: I групу склали хворі, які отримували ТАРЕ більше 6 місяців у дозі ≤ 50 мкг/міс (n = 20), до II групи увійшли хворі, у яких доза ТАРЕ склала ≥ 125 мкг/міс (n = 18). Поряд із стандартними діагностичними методами досліджували концентрацію малонового діальдегіду у сироватці (МДА) й еритроцитах (MДAe), вміст у крові церулоплазміну (ЦП) та трансферину (ТР). Крім того, визначали загальну пероксидазну активність (ЗПА) у еритроцитах, проникність еритроцитарних мембран (ПЕМ), підрахували відсоток гемолізу.
 Результати. У ГД пацієнтів, які лікувались ТАРЕ у дозі ≥ 125 мкг/міс визначено підвищення концентрації ЦР (р = 0,007) та ТР (р = 0,0003), тоді як ЗПА була статистично значуще зниженою порівняно з ІІ групою (р = 0,02). Крім того, У пацієнтів І групи встановлено вищий відсоток гемолізу (р = 0,03) та ПЕМ (р ˂ 0,0001). Використовуючи модель пробіт-регресії, ми визначили дозозалежний вплив ТАРЕ на рівень ПЕМ: χ2 = 21; р ˂ 0,0001.
 Висновки. Таким чином, застосування ТАРЕ у дозі понад 125 мкг на місяць покращує антиоксидантний статус ГД хворих, але разом з тим, підвищує гемоліз еритроцитів та ПЕМ. Отримані нами дані потребують подальшого підтвердження.

Low-Level Light Therapy Protects Red Blood Cells Against Oxidative Stress and Hemolysis During Extracorporeal Circulation.

Aim: An activation of non-specific inflammatory response, coagulation disorder, and blood morphotic elements damage are the main side effects of the extracorporeal circulation (ECC). Red-to-near-infrared radiation (R/NIR) is thought to be capable of stabilizing red blood cell (RBC) membrane through increasing its resistance to destructive factors. We focused on the development of a method using low-level light therapy (LLLT) in the spectral range of R/NIR which could reduce blood trauma caused by the heart-lung machine during surgery.Methods: R/NIR emitter was adjusted in terms of geometry and optics to ECC circuit. The method of extracorporeal blood photobiomodulation was tested during in vivo experiments in an animal, porcine model (1 h of ECC plus 23 h of animal observation). A total of 24 sows weighing 90–100 kg were divided into two equal groups: control one and LLLT. Blood samples were taken during the experiment to determine changes in blood morphology [RBC and white blood cell (WBC) counts, hemoglobin (Hgb)], indicators of hemolysis [plasma-free hemoglobin (PFHgb), serum bilirubin concentration, serum lactate dehydrogenase (LDH) activity], and oxidative stress markers [thiobarbituric acid reactive substances (TBARS) concentration, total antioxidant capacity (TAC)].Results: In the control group, a rapid systemic decrease in WBC count during ECC was accompanied by a significant increase in RBC membrane lipids peroxidation, while in the LLLT group the number of WBC and TBARS concentration both remained relatively constant, indicating limitation of the inflammatory process. These results were consistent with the change in the hemolysis markers like PFHgb, LDH, and serum bilirubin concentration, which were significantly reduced in LLLT group. No differences in TAC, RBC count, and Hgb concentration were detected.Conclusion: We presented the applicability of the LLLT with R/NIR radiation to blood trauma reduction during ECC.

Specific oxygenation of plasma membrane phospholipids by Pseudomonas aeruginosa lipoxygenase induces structural and functional alterations in mammalian cells

Pseudomonas aeruginosa is a gram-negative pathogen, which causes life-threatening infections in immunocompromized patients. These bacteria express a secreted lipoxygenase (PA-LOX), which oxygenates free arachidonic acid to 15S-hydro(pero)xyeicosatetraenoic acid. It binds phospholipids at its active site and physically interacts with lipid vesicles. When incubated with red blood cells membrane lipids are oxidized and hemolysis is induced but the structures of the oxygenated membrane lipids have not been determined. Using a lipidomic approach, we analyzed the formation of oxidized phospholipids generated during the in vitro incubation of recombinant PA-LOX with human erythrocytes and cultured human lung epithelial cells. Precursor scanning of lipid extracts prepared from these cells followed by multiple reaction monitoring and MS/MS analysis revealed a complex mixture of oxidation products. For human red blood cells this mixture comprised forty different phosphatidylethanolamine and phosphatidylcholine species carrying oxidized fatty acid residues, such as hydroxy-octadecadienoic acids, hydroxy- and keto-eicosatetraenoic acid, hydroxy-docosahexaenoic acid as well as oxygenated derivatives of less frequently occurring polyenoic fatty acids. Similar oxygenation products were also detected when cultured lung epithelial cells were employed but here the amounts of oxygenated lipids were smaller and under identical experimental conditions we did not detect major signs of cell lysis. However, live imaging indicated an impaired capacity for trypan blue exclusion and an augmented mitosis rate. Taken together these data indicate that PA-LOX can oxidize the membrane lipids of eukaryotic cells and that the functional consequences of this reaction strongly depend on the cell type.

Changes in Red Blood Cell membrane lipid composition: A new perspective into the pathogenesis of PKAN.

Pantothenate Kinase-Associated Neurodegeneration (PKAN) is a form of Neurodegeneration with Brain Iron Accumulation (NBIA) associated with mutations in the pantothenate kinase 2 gene (PANK2). The PANK2 catalyzes the first step of coenzyme A (CoA) biosynthesis, a pathway producing an essential cofactor that plays a key role in energy and lipid metabolism. The majority of PANK2 mutations reduces or abolishes the activity of the enzyme. In around 10% of cases with PKAN, the presence of deformed red blood cells with thorny protrusions in the circulation has been detected. Changes in membrane protein expression and assembly during erythropoiesis were previously explored in patients with PKAN. However, data on red blood cell membrane phospholipid organization are still missing in this disease. In this study, we performed lipidomic analysis on red blood cells from Italian patients affected by PKAN with a particular interest in membrane physico-chemical properties. We showed an increased number of small red blood cells together with membrane phospholipid alteration, particularly a significant increase in sphingomyelin (SM)/phosphatidylcholine (PC) and SM/phosphatidylethanolamine (PE) ratios, in subjects with PKAN. The membrane structural abnormalities were associated with membrane fluidity perturbation. These morphological and functional characteristics of red blood cells in patients with PKAN offer new possible tools in order to shed light on the pathogenesis of the disease and to possibly identify further biomarkers for clinical studies.

Disorders in structural-functional properties of erythrocytes in experimental acute destructive pancreatitis of alcohol etiology and their correction

The effects of various combinations of pharmacological agents on parameters characterizing red blood cell (RBC) membrane proteins and lipids have been investigated in RBC isolated from Wistar male rats with acute destructive pancreatitis induced under conditions of forced alcoholization for 60 days. Administration of a combination of Hepon, Hypoxenum, and Phosphogliv normalized 22.5% of parameters altered change during development of acute destructive pancreatitis under conditions of chronic alcoholization of parameters, corrected towards normal values 42.5% of parameters (35% of parameters remained unchanged). Administration of Glutoxim, Mexidol and Heptral, was more effective: this combination normalized 50.0% of parameters studied, corrected towards normal values 37.5% of parameters, leaving unchanged only 12.5% of parameters studied.

Membrane lipidomics in schizophrenia patients: a correlational study with clinical and cognitive manifestations.

Schizophrenia is a severe mental condition in which several lipid abnormalities—either structural or metabolic—have been described. We tested the hypothesis that an abnormality in membrane lipid composition may contribute to aberrant dopamine signaling, and thereby symptoms and cognitive impairment, in schizophrenia (SCZ) patients. Antipsychotic-medicated and clinically stable SCZ outpatients (n=74) were compared with matched healthy subjects (HC, n=40). A lipidomic analysis was performed in red blood cell (RBC) membranes examining the major phospholipid (PL) classes and their associated fatty acids (FAs). Clinical manifestations were examined using the positive and negative syndrome scale (PANSS). Cognitive function was assessed using the Continuous Performance Test, Salience Attribution Test and Wisconsin Card Sorting Test. Sphingomyelin (SM) percentage was the lipid abnormality most robustly associated with a schizophrenia diagnosis. Two groups of patients were defined. The first group (SCZ c/SM−) is characterized by a low SM membrane content. In this group, all other PL classes, plasmalogen and key polyunsaturated FAs known to be involved in brain function, were significantly modified, identifying a very specific membrane lipid cluster. The second patient group (SCZ c/SM+) was similar to HCs in terms of RBC membrane SM composition. Compared with SCZ c/SM+, SCZ c/SM− patients were characterized by significantly more severe PANSS total, positive, disorganized/cognitive and excited psychopathology. Cognitive performance was also significantly poorer in this subgroup. These data show that a specific RBC membrane lipid cluster is associated with clinical and cognitive manifestations of dopamine dysfunction in schizophrenia patients. We speculate that this membrane lipid abnormality influences presynaptic dopamine signaling.

Red blood cell membrane-mediated fusion of hydrophobic quantum dots with living cell membranes for cell imaging.

Nanoparticle fusion with cell membranes is an interesting phenomenon that may have crucial implications for their biomedical applications. Here, we proposed a biomimetic and controlled route to fusion of hydrophobic quantum dots (QDs) with the cell membranes of living cells, while preserving their sensing and optical properties and thus their capability of membrane imaging and single-nanoparticle tracking. Red blood cell (RBC) membrane lipids were extracted to phase transfer hydrophobic QDs and the resulting RBC-encapsulated QDs (RBC-QDs) can be well fused within cell membranes as membrane markers. The fusion was validated through single-nanoparticle imaging and different movement behaviours were reliably discriminated. RBC-QDs possessed some novel features, such as controllable selective membrane staining, no invasion, and high photobleaching resistance, which allowed for long-term imaging, and single-nanoparticle tracking. This approach provides a versatile platform for controlled hydrophobic QD-based fluorescence investigation of living cell membranes.

Association of n3 and n6 polyunsaturated fatty acids in red blood cell membrane and plasma with severity of normal tension glaucoma.

To determine whether red blood cell (RBC) membrane and plasma lipids, particularly long-chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA) are significantly correlated with severity of normal tension glaucoma (NTG). This study included 35 patients with NTG and 12 healthy normal control subjects, matched for age and sex with the study group. The stage of glaucoma was determined according to the Hodapp-Parrish-Anderson classification. Lipids were extracted from RBC membranes and plasma, and fatty acid methyl esters prepared and analyzed by gas chromatography-mass spectrometry (GC-MS). When RBC lipids were analyzed, the levels of EPA, the levels of DHA and the ratio of n3 to n6 were positively associated with the Humphrey Perimetry mean deviation (MD) score (r=0.617, P<0.001; r=0.727, P<0.001 and r=0.720, P<0.001, respectively), while the level of AA was negatively associated with the MD score (r=-0.427, P=0.001). When plasma lipids were analyzed, there was a significant positive relationship between the levels of EPA and the MD score (r=0.648, P<0.001), and the levels of AA were inversely correlated with the MD score (r=-0.638, P<0.001). The levels of n3 and n6 polyunsaturated fatty acids in RBC membrane and plasma lipids were associated with severity of NTG.

Evaluation of the actions of metformin and taurine, singly and in combination, on metabolic and oxidative alterations caused by diabetes in rat erythrocytes and plasma.

This study has compared the actions of metformin (MET) and taurine (TAU), singly and in combination, on diabetes-induced metabolic and oxidative alterations in a chemical rat model of diabetes. Groups of six male Sprague-Dawley rats, 225–250 g, were used in the study. Diabetes was induced on day 1 with streptozotocin, 60 mg/kg, i.p. The rats were then separately treated with MET, TAU or MET plus TAU, each at a 2.4 mM/kg/day p.o., or with insulin, 4 U/kg/day s.c., from day 15 to day 56. Blood samples were collected on day 57. One portion was assayed for HbA1c and the other was used to obtain plasma and red blood cells (RBCs). The plasma was used to measure glucose, insulin, and hemoglobin levels, and indices of oxidative stress; and the RBCs were analyzed for hemoglobin content, membrane ratio of cholesterol to phospholipids, and indices of oxidative stress. In comparison to normal rats, diabetic ones showed a marked increase in plasma glucose and blood HbA1c level, a lower plasma insulin, and evidence of significant hemolysis. In addition, oxidative stress was detected in the plasma and RBCs, and the RBC membrane ratio of cholesterol to phospholipids was higher in diabetic than in normal specimens. MET was more effective than TAU in attenuating the changes in circulating glucose, insulin and HbA1c levels, about equipotent in lowering changes in RBC membrane lipids and in preserving the RBC redox status, and weaker in attenuating changes in indices of oxidative stress. When used together, TAU was found to enhance the antioxidant actions of MET both in the plasma and RBCs. The present results suggest that MET and TAU are more protective against diabetes-induced metabolic and oxidative alterations when used together than separately, probably because of complementary actions.

Changes of Molecular Glycerophospholipid Species in Plasma and Red Blood Cells During Docosahexaenoic Acid Supplementation

Docosahexaenoic acid (DHA) status is related to health and disease risk. DHA status is mainly determined by dietary DHA intake, since endogenous synthesis of DHA is limited. We aimed to investigate the changes of different molecular glycerophospholipid species containing DHA in plasma and red blood cells (RBC) in response to increased DHA intake. Thirteen healthy adults had their diet supplemented with 510 mg DHA/day for 29 days. Fasted blood samples were taken at 11 time points and glycerophospholipid species were analyzed by liquid chromatography mass spectrometry. In plasma, percentages of glycerophospholipid species containing DHA increased significantly by 64-104 % relative to baseline values during supplementation, but the relative distribution between species was not markedly altered. In RBC, phosphatidylcholine (PtdCho) species containing DHA increased to a similar extent as in plasma, while phosphatidylethanolamine and phosphatidylserine species with DHA increased by only 12-25 %, respectively, which was significantly different compared to PtdCho species (p < 0.01). Despite the high increase, the contribution of DHA PtdCho species to total DHA remained minor (14 % after supplementation). In conclusion, DHA supplementation does not alter the relative distribution of DHA among glycerophospholipid species in plasma. A majority of PtdCho species are rapidly exchanged between plasma lipoproteins and RBC membrane lipids, while there is a minor exchange of phosphatidylethanolamine and phosphatidylserine species.

Do High Levels of n-3 Polyunsaturated Fatty Acids in Cell Membranes Increase the Risk of Postoperative Atrial Fibrillation?

Objectives: Postoperative atrial fibrillation (POAF) has been associated with an inflammatory response to the surgical procedure. n-3 long-chain polyunsaturated fatty acids (LC-PUFA) have been proposed for the prevention of POAF. We investigated the relationship between the plasma concentration of inflammatory mediators, levels of n-3 LC-PUFA in red blood cell (RBC) membrane lipids, and the risk of POAF after coronary artery bypass grafting (CABG). Methods: A total of 125 patients who underwent CABG were studied. Inflammatory mediators in plasma and the content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in RBC membranes were assessed. Results: Sixty-two patients (49.6%) developed POAF. The POAF group had higher RBC levels of total n-3 LC-PUFA and DHA than did patients remaining in sinus rhythm (p < 0.05). Of the inflammatory mediators, only postoperative interleukin-6 levels differed, being higher in the POAF group (p < 0.05). Inflammatory mediators were not independent predictors of POAF by multivariable logistic regression analysis. Higher levels of DHA and total n-3 LC-PUFA in RBC membranes, measured immediately prior to CABG and on postoperative day 3, were linearly associated with an increased risk of POAF (p < 0.05). Conclusions: Our findings suggest that inflammatory mediators are not associated with the occurrence of POAF. Interestingly, high n-3 LC-PUFA levels in RBC membranes appear to increase the risk of POAF.

Inflammatory response following heart surgery and association with n−3 and n−6 long-chain polyunsaturated fatty acids in plasma and red blood cell membrane lipids

BackgroundOpen heart surgery is associated with a systemic inflammatory response. The n−3 long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the n−6 LC-PUFA arachidonic acid (AA) may contribute to modulation of the inflammatory response. ObjectiveWe investigated whether the preoperative levels of EPA, DHA and AA in plasma phospholipids (PL) and red blood cell (RBC) membrane lipids in patients (n=168) undergoing open heart surgery were associated with changes in the plasma concentration of selected inflammatory mediators in the immediate postoperative period. Results and conclusionsThe postoperative concentration of TNF-β was lower (P<0.05) and those of hs-CRP, IL-6, IL-8, IL-18 and IL-10 higher (P<0.05) than the respective preoperative concentrations. We observed that the preoperative levels of EPA and AA in plasma PL and RBC membrane lipids were associated with changes in the concentration of pro-inflammatory and anti-inflammatory mediators, suggesting a complex role in the postoperative inflammatory process.