Permeability Of Red Blood Cells Research Articles

A Gardos channelopathy associated with nonimmune hydrops and fetal loss.

Dehydrated hereditary stomatocytosis (DHS) (MIM#194380) is a rare autosomal dominant disorder of red blood cell permeability, characterized by a partially or fully compensated nonimmune hemolytic anemia. PIEZO1 is the major gene involved with hundreds of families described, some of which present transient perinatal edema of varying severity. A smaller subset of individuals harbors pathogenic variants in KCNN4, sometimes referred as "Gardos channelopathy." Up to now, only six pathogenic variants in KCNN4 have been reported in 13 unrelated families. Unlike PIEZO1-DHS, neither perinatal edema nor fetal loss has ever been observed linked to KCNN4-DHS. We report the first fetal loss due to non-immune hydrops fetalis related to a pathogenic 28 bp deletion (NM_002250.2: c.1109_1119+17del) in KCNN4. This observation underlies the need for very close monitoring of pregnancies when one parent is affected by DHS regardless of genotype (PIEZO1 or KCNN4).

Mechanosensitive Pannexin 1 Activity Is Modulated by Stomatin in Human Red Blood Cells.

Pannexin 1 (PANX1) was proposed to drive ATP release from red blood cells (RBCs) in response to stress conditions. Stomatin, a membrane protein regulating mechanosensitive channels, has been proposed to modulate PANX1 activity in non-erythroid cells. To determine whether stomatin modulates PANX1 activity in an erythroid context, we have (i) assessed the in situ stomatin-PANX1 interaction in RBCs, (ii) measured PANX1-stimulated activity in RBCs expressing stomatin or from OverHydrated Hereditary Stomatocytosis (OHSt) patients lacking stomatin, and in erythroid K562 cells invalidated for stomatin. Proximity Ligation Assay coupled with flow imaging shows 27.09% and 6.13% positive events in control and OHSt RBCs, respectively. The uptake of dyes 5(6)-Carboxyfluorescein (CF) and TO-PRO-3 was used to evaluate PANX1 activity. RBC permeability for CF is 34% and 11.8% in control and OHSt RBCs, respectively. PANX1 permeability for TO-PRO-3 is 35.72% and 18.42% in K562 stom+ and stom− clones, respectively. These results suggest an interaction between PANX1 and stomatin in human RBCs and show a significant defect in PANX1 activity in the absence of stomatin. Based on these results, we propose that stomatin plays a major role in opening the PANX1 pore by being involved in a caspase-independent lifting of autoinhibition.

Light and Scanning Electron Microscopy of Red Blood Cells From Humans and Animal Species Providing Insights into Molecular Cell Biology.

We reviewed the many discoveries in cell biology, made since the 17th century, which have been based on red blood cells (RBCs). The advances in molecular and structural biology in the past 40 years have enabled the discovery with these cells, most notably, of the first water channel protein (WCP) called today aquaporin1 (AQP1). The main aim of our work reviewed was to examine by light and electron microscopy a very wide range of RBCs from reptiles, birds, monotremes, marsupials and placentals, in order to estimate from these images the RBC cell volume and surface area. The diffusional water permeability of the RBC membrane from these species has further been measured with a nuclear magnetic resonance (NMR) spectroscopy technique. The significance of the observed permeability of RBCs to water and possible influences on the whole body are discussed.

Clinical Performance Study of a New Fully Automated Red Blood Cell Permeability Fragility Analyzer.

In order to verify the applicability of the erythrocyte fragility test (EFT) carried out by the new fully automatic erythrocyte permeability fragility analyzer RA-800 for thalassemia screening, a total of 100 cases of suspected thalassemia patients who underwent pregnancy examinations at Luohu District People's Hospital are included. The results of a new automatic erythrocyte permeability fragility analyzer RA-800 are compared with the results of the detection system composing of the KOFA erythrocyte fragility test kit currently used in clinical laboratories. The diagnosis confirmed by genetic testing is used as the gold standard to evaluate the applicability of RA-800. The sensitivity, specificity, and accuracy of the new automatic erythrocyte permeability fragility analyzer RA-800 screening for thalassemia were 66.67%, 92.86%, and 85.00%. The KOFA direct colorimetries are 76.67%, 81.43%, and 80.00%. The kappa value for the screening of thalassemia was 0.558, which concludes that the consistency was moderate. The ROC curve indicates that both two methods had diagnostic significance for the diagnostic value of thalassemia. The new automatic erythrocyte permeability fragility analyzer RA-800 is suitable for thalassemia screening, and the performance indexes meet the clinical requirements.

Hereditary Xerocytosis: Differential Behavior of PIEZO1 Mutations in the N-Terminal Extracellular Domain Between Red Blood Cells and HEK Cells.

Hereditary Xerocytosis, a rare hemolytic anemia, is due to gain of function mutations in PIEZO1, a non-selective cation channel activated by mechanical stress. How these PIEZO1 mutations impair channel function and alter red blood cell (RBC) physiology, is not completely understood. Here, we report the characterization of mutations in the N-terminal part of the protein (V598M, F681S and the double mutation G782S/R808Q), a part of the channel that was subject of many investigations to decipher its role in channel gating. Our data show that the electrophysiological features of these PIEZO1 mutants expressed in HEK293T cells are different from previously characterized PIEZO1 mutations that are located in the pore or at the C-terminal extracellular domain of the protein. Although RBC with PIEZO1 mutations showed a dehydrated phenotype, the activity of V598M, F681S or R808Q in response to stretch was not significantly different from the WT channels. In contrast, the G782S mutant showed larger currents compared to the WT PIEZO1. Interestingly, basal activity of all the mutated channels was not significantly altered at the opposite of what was expected according to the decreased water and cation contents of resting RBC. In addition, the features of mutant PIEZO1 expressed in HEK293 cells do not always correlate with the observation in RBC where PIEZO1 mutations induced a cation leak associated with an increased conductance. Our work emphasizes the role of the membrane environment in PIEZO1 activity and the need to characterize RBC permeability to assess pathogenicity to PIEZO1 mutants associated with erythrocyte diseases.

The effect of the antisickling compound GBT1118 on the permeability of red blood cells from patients with sickle cell anemia.

Sickle cell anemia (SCA) is one of the commonest severe inherited disorders. Nevertheless, effective treatments remain inadequate and novel ones are avidly sought. A promising advance has been the design of novel compounds which react with hemoglobin S (HbS) to increase oxygen (O2) affinity and reduce sickling. One of these, voxelotor (GBT440), is currently in advanced clinical trials. A structural analogue, GBT1118, was investigated in the current work. As RBC dehydration is important in pathogenesis of SCA, the effect of GBT1118 on RBC cation permeability was also studied. Activities of Psickle, the Gardos channel and the KCl cotransporter (KCC) were all reduced. Gardos channel and KCC activities were also inhibited in RBCs treated with Ca2+ ionophore or the thiol reagent N‐ethylmaleimide, indicative of direct effects on these two transport systems. Consistent with its action on RBC membrane transporters, GBT1118 significantly increased RBC hydration. RBC hemolysis was reduced in a nonelectrolyte lysis assay. Further to its direct effects on O2 affinity, GBT1118 was therefore found to reduce RBC shrinkage and fragility. Findings reveal important effects of GBT1118 on protecting sickle cells and suggest that this is approach may represent a useful therapy for amelioration of the clinical complications of SCA.

Research Progress on the Laboratory Diagnosis for Thalassemia -Review

Thalassemia laboratory diagnostic techniques include screening test and genetic test, the former diagnosis method is mainly based on the morphology of red blood cells and the physical and chemical properties, including routine analysis of blood, red blood cell morphology test, red blood cell permeability test, hemoglobin component analysis, etc. The latter is mainly based on various of molecular biology experiments developed on the basis of PCR, including gap-PCR,PCR-RDB,melting curve analysis,high resolution melting analysis,real-time PCR,gene chip and DNA sequencing, etc. This paper reviews the progress of laboratory diagnostic techniques on thalassemia, combination of comprehensive screening method with technique of genetic diagnosis, appropriately contributes to the diagnosis of thalassemia.

On the Mechanism of Human Red Blood Cell Longevity: Roles of Calcium, the Sodium Pump, PIEZO1, and Gardos Channels.

In a healthy adult, the transport of O2 and CO2 between lungs and tissues is performed by about 2 · 1013 red blood cells, of which around 1.7 · 1011 are renewed every day, a turnover resulting from an average circulatory lifespan of about 120 days. Cellular lifespan is the result of an evolutionary balance between the energy costs of maintaining cells in a fit functional state versus cell renewal. In this Review we examine how the set of passive and active membrane transporters of the mature red blood cells interact to maximize their circulatory longevity thus minimizing costs on expensive cell turnover. Red blood cell deformability is critical for optimal rheology and gas exchange functionality during capillary flow, best fulfilled when the volume of each human red blood cell is kept at a fraction of about 0.55–0.60 of the maximal spherical volume allowed by its membrane area, the optimal-volume-ratio range. The extent to which red blood cell volumes can be preserved within or near these narrow optimal-volume-ratio margins determines the potential for circulatory longevity. We show that the low cation permeability of red blood cells allows volume stability to be achieved with extraordinary cost-efficiency, favouring cell longevity over cell turnover. We suggest a mechanism by which the interplay of a declining sodium pump and two passive membrane transporters, the mechanosensitive PIEZO1 channel, a candidate mediator of Psickle in sickle cells, and the Ca2+-sensitive, K+-selective Gardos channel, can implement red blood cell volume stability around the optimal-volume-ratio range, as required for extended circulatory longevity.

Red Cell Transport Abnormalities As Predictors of the Development of Renal Disease in Children with Sickle Cell Disease

Background:Patients with sickle cell disease (SCD) have the abnormal haemoglobin (Hb) HbS in their red blood cells (RBCs). The complications of SCD may be extensive but are markedly variable between patients. Renal damage (sometimes called sickle cell nephropathy, SCN) is a common finding in about a third of children with SCD, a significant number of whom will proceed to renal failure. As yet, it is not possible to predict which children will develop SCN and who would therefore benefit from earlier and aggressive management. Various biomarkers have been investigated but none have proved efficacious. Changes in RBC membrane permeability are closely linked with polymerisation of HbS and, as such, may represent an important early event in pathogenesis.We postulated that certain RBC characteristics (sickling, K+ transport, PS exposure), which may be inherited independently of the HbS mutation, may correlate with renal pathology, but more importantly, may be identifiable in advance of damage, thereby providing prognostic markers to inform patient management.Participants and Methods:Children (>4 years old) with sickle cell anaemia (SCA) were recruited from the paediatric haematology clinic at King’s College Hospital in South London, UK. Patients who had received blood transfusion in the preceding four months or who were on medications known to directly alter RBC cation transport (e.g. dipyridamole and Ca2+ channel blockers) were excluded. Patients on hydroxyurea were included. All patients were in steady state, with no acute symptoms requiring treatment for at least seven days. Clinical and laboratory parameters were collected prospectively at routine clinical attendance. Details of enuresis were collected using specifically developed proforma and patients were divided into two groups: those who stopped wetting their bed before the age of five years and those who were still enuretic after five years of age. RBC permeability was assessed using 86Rb+ as a congener for K+ to measure the activity of main cation transport systems involved in RBC dehydration. The activity of RBC transport pathways and percentage of sickling was measured at 100mmHg, 35mmHg, 15mmHg and 0mmHg. Statistical analysis was conducted using IBM-SPSS, New York.Results: 112 patients of HbSS genotype (SCA) consented to take part in the study. Their clinical profile is summarised Table 1. The percentage of children with enuresis, hypertension and significant albuminuria is shown in Table 2. There was significant correlation between activity of Gardos channel at O2 tensions of 35mmHg, 15mmHg and 0mmHg and enuresis after the age of five years. Psickle activity also showed significant correlation but only in fully deoxygenated RBCs (O2 of 0mmHg.) Table 3.ConclusionIn conclusion, the present findings emphasise the significance of a thorough appreciation of RBC permeability to the pathogenesis of SCD. Whilst preliminary, these findings are exciting because they show that the activity of a particular transport pathways, abnormally elevated in SCA patients, are associated with enuresis. These findings suggest that the early identification of increased Gardos and Psickle activity may identify children who would benefit from early treatment for nocturnal enuresis. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Study of the derivatives of 1-adamantane carboxylic acid to induced plateletaggregation human in vitro

The study of condition of the system of hemoglobin, release of peptide com- pounds, and proteolytic activity of human erythrocytes under conditions of hy- perglycemia of varying degrees is carried out. The increase in the level of hy- perglycemia is accompanied by a decrease of affinity of hemoglobin to oxygen and the growth of level of metgemoglobin, the glycosylated hemoglobin level is increased in conditions of severe hyperglycemia. The level of formation of pep- tides in erythrocytes and the level of output of their cells is determined by the increase in trypsin-like activity in cytosol and increased membrane permeability of red blood cells.

STATE SYSTEM OF HEMOGLOBIN AND THE ACTIVITY OF ENZYMES OF HUMAN ERYTHROCYTES UNDER CONDITIONS OF HYPERGLYCEMIA IN VITRO

The study of condition of the system of hemoglobin, release of peptide com- pounds, and proteolytic activity of human erythrocytes under conditions of hy- perglycemia of varying degrees is carried out. The increase in the level of hy- perglycemia is accompanied by a decrease of affinity of hemoglobin to oxygen and the growth of level of metgemoglobin, the glycosylated hemoglobin level is increased in conditions of severe hyperglycemia. The level of formation of pep- tides in erythrocytes and the level of output of their cells is determined by the increase in trypsin-like activity in cytosol and increased membrane permeability of red blood cells.

Morphology and water permeability of red blood cells from green sea turtle (Chelonia mydas).

The morphology and diffusional water permeability (P d) of red blood cells (RBCs) from green sea turtle (GST) (Chelonia mydas) are presented for the first time. The RBCs had an ellipsoidal shape with full-axis lengths (diameters): D = 14.4μm; d = 10.2μm; h = 2.8μm. The values of P d (cms(-1)) were 5.1 × 10(-3) at 15°C, 5.7 × 10(-3) at 20°C, 6.3 × 10(-3) at 25°C, 6.8 × 10(-3) at 30°C, and 7.9 × 10(-3) at 37°C (i.e., significantly higher than in human RBCs in which it was measured to be 4.2 × 10(-3) at 25°C, 5.0 × 10(-3) at 30°C, and 6.2 × 10(-3) at 37°C). There was a lack of inhibition of P d of GST RBCs by p-chloromercuribenzoate (PCMB), a well-known inhibitor of the RBC water channel proteins (WCPs). The activation energy of water diffusion (E a,d) in GST RBCs was 15.0 ± 1.6kJmol(-1) which is lower than the E a,d for human RBCs (~25kJmol(-1)). These results indicate that in the membrane of GST RBCs, there were no WCPs that were inhibited by the mercurial reagent, while the lipid bilayer of this membrane is unusually permeable to water. This is likely to be a phylogenetically old trait, like that found in amphibians and even the later birds, all of which have nucleated erythrocytes; and it is also likely to be a result of the animal's adaptation to a herbivorous diet (algae and seagrasses).

Effects of 5-hydroxymethyl-2-furfural on the volume and membrane permeability of red blood cells from patients with sickle cell disease.

The heterocyclic aldehyde 5-hydroxymethyl-2-furfural (5HMF) interacts allosterically with the abnormal form of haemoglobin (Hb), HbS, in red blood cells (RBCs) from patients with sickle cell disease (SCD), thereby increasing oxygen affinity and decreasing HbS polymerization and RBC sickling during hypoxia. We hypothesized that should 5HMF also inhibit the main cation pathways implicated in the dehydration of RBCs from SCD patients - the deoxygenation-induced cation pathway (Psickle), the Ca(2+)-activated K(+) channel (the Gardos channel) and the K(+)-Cl(-) cotransporter (KCC) - it would have a synergistic effect in protection against sickling, directly through interacting with HbS, and indirectly through maintaining hydration and reducing [HbS]. This study was therefore designed to investigate the effects of 5HMF on RBC volume and K(+) permeability in vitro. 5HMF markedly reduced the deoxygenation-induced dehydration of RBCs whether in response to maintained deoxygenation or to cyclical deoxygenation/re-oxygenation. 5HMF was found to inhibit Psickle, an effect which correlated with its effects on sickling. Deoxygenation-induced activation of the Gardos channel and exposure of phosphatidylserine were also inhibited, probably indirectly via reduced entry of Ca(2+) through the Psickle pathway. Effects of 5HMF on KCC were more modest with a slight inhibition in N-ethylmaleimide (NEM, 1 mm)-treated RBCs and stimulation in RBCs untreated with NEM. These findings support the hypothesis that 5HMF may also be beneficial through effects on RBC ion and water homeostasis.

A method to measure permeability of red blood cell membrane to water and solutes using intrinsic fluorescence

BackgroundDesigning effective cryopreservation procedures for cells requires knowledge of permeability of cell membrane to water and solutes. To determine cell membrane permeability, one needs to measure the rate of cell volume changes in anisotonic environment. Red blood cells (RBCs) respond very quickly to changes in extracellular solutes concentration, which complicates the use of traditional methods. Preservation of RBCs from umbilical cord blood for neonatal transfusions is currently broadly discussed in the literature, but data on osmotic permeability of cord RBCs is controversial. Therefore, alternative methods to determine osmotic membrane permeability of these cells are warranted. We describe a technique to measure rapid changes in RBC volume through changes in the intensity of RBC autofluorescence. MethodsTo induce osmotically-driven changes in RBC volume, we rapidly mixed human RBCs with anisotonic solutions in a stopped-flow spectroscopy system and the intensity of intrinsic RBC fluorescence was measured. ResultsWe found that change in RBC volume cause a proportional change in the intensity of RBC autofluorescence. This phenomenon occurs due to the self-quenching of RBC hemoglobin autofluorescence at high intracellular concentrations. ConclusionsThis novel method to determine osmotic permeability of RBCs overcomes the limitations of traditional techniques and has numerous clinical applications.

The permeability of red blood cells to chloride, urea, and water

This study extends permeability (P) data on chloride, urea and water in red blood cells (RBC), and concludes that the urea transporter (UT-B) does not transport water. P of chick, duck, Amphiuma means, dog and human RBC to (36)Cl(-), (14)C-urea and (3)H2O was determined under self-exchange conditions. At 25°C and pH 7.2-7.5, PCl is 0.94 × 10(-4)-2.15 × 10(-4) cm s(-1) for all RBC species at [Cl]=127-150 mmol l(-1). In chick and duck RBC, P(urea) is 0.84 × 10(-6) and 1.65 × 10(-6) cm s(-1), respectively, at [urea]=1-500 mmol l(-1). In Amphiuma, dog and human RBC, P(urea) is concentration dependent (1-1000 mmol l(-1), Michaelis-Menten-like kinetics; K1/2;=127, 173 and 345 mmol l(-1)), and values at [urea]=1 mmol l(-1) are 29.5 × 10(-6), 467 × 10(-6) and 260 × 10(-6) cm s(-1), respectively. Diffusional water permeability, Pd, was 0.84 × 10(-3) (chick), 5.95 × 10(-3) (duck), 0.39 × 10(-3) (Amphiuma), 3.13 × 10(-3) (dog) and 2.35 × 10(-3) cm s(-1) (human). DIDS, DNDS and phloretin inhibit PCl by >99% in all RBC species. PCMBS, PCMB and phloretin inhibit P(urea) by >99% in Amphiuma, dog and human RBC, but not in chick and duck RBC. PCMBS and PCMB inhibit Pd in duck, dog and human RBC, but not in chick and Amphiuma RBC. Temperature dependence, as measured by apparent activation energy, EA, of PCl is 117.8 (duck), 74.9 (Amphiuma) and 89.6 kJ mol(-1) (dog). The EA of P(urea) is 69.6 (duck) and 53.3 kJ mol(-1) (Amphiuma), and that of Pd is 34.9 (duck) and 32.1 kJ mol(-1) (Amphiuma). The present and previous RBC studies indicate that anion (AE1), urea (UT-B) and water (AQP1) transporters only transport chloride (all species), water (duck, dog, human) and urea (Amphiuma, dog, human), respectively. Water does not share UT-B with urea, and the solute transport is not coupled under physiological conditions.

69. All that’s needed is inside the cell: New method to measure permeability of red blood cell membrane using intrinsic fluorescence

To design effective cryopreservation procedures for cells and tissues, it is critical to know permeability of cell membrane to water and solutes. To determine the latter, one needs to measure the rate of cell volume changes when placed in anisotonic environment. Red blood cells (RBCs) respond very quickly to changes in extracellular solutes concentration, which makes it difficult to measure the rate of RBC volume change using traditional methods. Stopped-flow method captures rapid changes of RBC volume and is a common method to measure RBC osmotic permeability. There are two types of stopped-flow methods: the first measures RBC volume based on changes in the intensity of light scattered by RBCs (Sidel and Solomon, 1957), the second measures it based on the self-quenching of fluorescent dye entrapped inside RBCs (Chen et al., 1988). However, both techniques have flaws. A number of factors other than cell volume influence the intensity of scattered light (Chen et al., 1988). Absorbance of a significant portion of emitted fluorescent light by the broad spectrum of hemoglobin complicates the fluorescent quenching technique. Literature shows that RBC hemoglobin has autofluorescent properties (Hirstch, 2003). This work explored the possibility of using intrinsic fluorescence of intracellular hemoglobin to measure RBC permeability to water and solutes. Network Center for Applied Development in Vancouver provided adult RBCs for this study. We used SX20 stopped-flow reaction analyser (Applied Photophysics) to measure changes in RBC autofluorescence when mixed with sodium chloride or glycerol solutions of different concentration (excitation 280 nm, emission 314 nm). Equilibrium volumes of RBCs in sodium chloride solutions were measured on Coulter Counter Model ZBI (Coulter Electronics, Inc.). Lysed RBCs served as a negative control to verify that changes in autofluorescence intensity are caused by the changes in volume of intact RBCs. We also measured absolute values of autofluorescence as a function of hemoglobin concentration in the solution using SpectraMax GEMINI EM dual-scanning microplate spectrofluorometer (Molecular devices). Our results showed that the intensity of RBC autofluorescence and RBC volume measured on Coulter Counter were directly related. Specifically, mixing RBCs with hypotonic solution caused increase in cell volume and gradual increase in autofluorescence; cell shrinking in hypertonic solution resulted in autofluorescence decrease. On the contrary, tonicity of solution had no effect on autofluorescence of lysed RBCs. When RBCs were injected in glycerol solution, autofluorescence first dropped, then gradually increased, and finally reached a plateau. This response is similar to the well-known pattern of cell volume changes upon mixing with permeable cryoprotectant. We also found that at high (intracellular) hemoglobin concentrations fluorescence intensity and hemoglobin concentration are inversely related. Combined, our data shows that RBC autofluorescence is directly translated to RBC volume, and self-quenching of intracellular hemoglobin is responsible for the cell volume driven changes in RBC autofluorescence. Based on these findings, we are working on developing a new method to determine osmotic permeability of RBCs, which will significantly help with future design and optimization of cryopreservation protocols.

Comparative studies of water permeability of red blood cells from humans and over 30 animal species: an overview of 20 years of collaboration with Philip Kuchel

NMR measurements of the diffusional permeability of the human adult red blood cell (RBC) membrane to water (P(d)) and of the activation energy (E(a,d)) of the process furnished values of P(d) ~ 4 × 10(-3) cm/s at 25 °C and ~6.1 × 10(-3) cm/s at 37 °C, and E(a,d) ~ 26 kJ/mol. Comparative NMR measurements for other species showed: (1) monotremes (echidna and platypus), chicken, little penguin, and saltwater crocodile have the lowest P(d) values; (2) sheep, cow, and elephant have P(d) values lower than human P(d) values; (3) cat, horse, alpaca, and camel have P(d) values close to those of humans; (4) guinea pig, dog, dingo, agile wallaby, red-necked wallaby, Eastern grey kangaroo, and red kangaroo have P(d) values higher than those of humans; (5) mouse, rat, rabbit, and "small and medium size" marsupials have the highest values of P(d) (>8.0 × 10(-3) cm/s at 25 °C and >10.0 × 10(-3) cm/s at 37 °C). There are peculiarities of E(a,d) values for the RBCs from different species. The maximum inhibition of diffusional permeability of RBCs induced by incubation with p-chloromercuribenzene sulfonate varied between 0% (for the chicken and little penguin) to ~50% (for human, mouse, cat, sheep, horse, camel, and Indian elephant), and ~60-75% (for rat, guinea pig, rabbit, dog, alpaca, and all marsupials). These results indicate that no water channel proteins (WCPs) or aquaporins are present in the membrane of RBCs from monotremes (echidna, platypus), chicken, little penguin and saltwater crocodile whereas WCPs from the membranes of RBCs from marsupials have peculiarities.

P4‐042: 1H nuclear magnetic resonance (NMR) studies of red blood cell permeability from patients with cardiovascular pathology

P4‐042: 1H nuclear magnetic resonance (NMR) studies of red blood cell permeability from patients with cardiovascular pathology

Role of membrane permeability and extracellular diffusion in nitric oxide transport to the red blood cells

Nitric oxide (NO) availability for vasodilation in vasculature is dependent on its consumption by red blood cell (RBC) hemoglobin. Extracellular diffusion in the plasma, cell free layer near the vessel wall and the RBC membrane permeability (Pm) reportedly lower NO consumption by RBCs. To understand the contribution of RBC membrane permeability and extracellular diffusion from the plasma layer surrounding the RBC towards NO uptake by RBCs, we developed a mathematical model simulating NO transport to a single RBC. Simulations were performed for Pm values ranging from 0.0415–40 cm/s and hematocrit (Hct) ranging from 1–45% and NO concentrations at the RBC membrane (CNOm inside and CNOm outside) were estimated. NO concentration gradients in the plasma layer increased with Pm. CNOm inside increased while CNOm outside decreased with Pm. At Pm =40 cm/s, CNOm inside and CNOm outside were similar to each other and both increased with Hct, indicating that extracellular diffusional resistance provides a significant transport barrier for NO at higher RBC membrane permeability. At Pm = 0.0415 cm/s, estimated CNOm outside were much higher than CNOm inside and both were independent of Hct for Hct ≥ 15%, suggesting that at lower RBC membrane permeability, for Hct ≥ 15%, RBC permeability is a major barrier for resistance for NO transport. Insights from this study may prove useful in understanding interaction of NO with RBC. Supported by AHA 0530050N & R15 HL087287 grants.

Вплив сукцинату натрію на еритроцити за окисного стресу при фізичних навантаженнях

On the basis of model experiments in vitro with application of sodium succinate which is the basic constituent of dietary supplementation "YantarIn-Sport", possibility of correction of the structurally-functional state of red blood cell membranes is well-proven. It is show that prooxidative-antioxidative balance in washed erythrocytes is normalized with the accumulation of recovered glutathione from 2.34 to 3.12 x 10(-12) mM in one erythrocyte, and their sorption ability (from 35.6 to 27.1% as well as red blood cells permeability (from 4.61 to 3.98 conditional units) are decreased. In vivo research the positive influence of sodium succinate on descriptions of red blood cells of skilled sportsmen is confirmed, that is founding for application of succinic acid derivatives with the purpose of sporting anaemia' warning as well as improvement of microcirculation processes and increase of speed blood flow.