Showing papers on "Red blood cell published in 2016"

Role of Glycated Proteins in the Diagnosis and Management of Diabetes: Research Gaps and Future Directions

Abstract: Blood oligosaccharides are attached to many proteins after translation, forming glycoproteins. Glycosylation refers to an enzyme-mediated modification that alters protein function, for example, their life span or their interactions with other proteins (1). By contrast, glycation refers to a monosaccharide (usually glucose) attaching nonenzymatically to the amino group of a protein. Glycated hemoglobin is formed by the condensation of glucose with select amino acid residues, commonly lysine, in hemoglobin to form an unstable Schiff base (aldimine, pre-HbA1c) (Fig. 1). The Schiff base may dissociate or may undergo an Amadori rearrangement to form a stable ketoamine. Figure 1 Formation of glycated protein. A reversible interaction between a primary amino group (depicted as NH2) of a protein and the carbonyl group of d-glucose yields a labile intermediate, called a Schiff base. This can undergo a slow and spontaneous Amadori rearrangement to form a stable ketoamine. HbA1c is formed if glucose attaches to the N-terminal valine of the β-chain of hemoglobin. If the glucose attaches to proteins in the plasma, fructosamine or glycated albumin results. RBC, red blood cell. Glycated hemoglobin, particularly HbA1c, has for decades been widely incorporated into the management (and, more recently, the diagnosis) of patients with diabetes. An important attribute is that glycation occurs continuously over the lifetime of the protein, so the concentration of the glycated protein reflects the average blood glucose value over a period of time. This contrasts with the measurement of blood glucose, which reveals the glucose concentration at the instant blood is sampled and which is acutely altered by multiple factors such as hormones, illness, food ingestion, and exercise (2). While HbA1c is by far the most extensively used—and studied—glycated protein (2–4), other glycated proteins that have been evaluated in clinical studies include fructosamine, glycated albumin, and …

On the Interactions of Lipids and Proteins in the Red Blood

Abstract: The effects of temperature and of the action of a purified phospho- lipase C enzyme preparation on human red blood cell membranes has been in- vestigated by chemical analyses, circular dichroism, and proton magnetic resonance measurements. The results indicate that a substantial fraction of the phospholipids and the proteins of the membranes can change structure in- dependently of one another, suggesting a mosaic pattern for the organization of the lipids and proteins in. membranes. The application of new or improved physical techniques to membrane systems has recently yielded some useful information about their structure. For ex- ample, optical rotatory dispersion and circular dichroism (CD) measurementst' 2 in the peptide bond absorption band have shown that a substantial fraction of the protein is in the a-helical conformation in several different membranes. Proton magnetic resonance (pmr) spectra of intact red blood cell membranes under physiological conditions show very broad resonances,3 suggesting that the lipid and protein constituents of the membranes are relatively immobile. Elec- tron spin resonance studies have yielded information about the mobility of spin- labeled adducts within membranes.4 Only limited information is available at present concerning the interactions between, and the organization of, the lipids and proteins of membranes. One approach to this problem is to perturb intact membranes in different well-defined ways, and by the use of a variety of techniques to determine the effects of the perturbations on the lipid and protein components. Phospholipase C is an enzyme that specifically catalyzes the hydrolysis of phospholipids to diglycerides and water-soluble phosphorylated amines.5 Lenard and Singer6 showed that treatment of red blood cell membranes with phospholipase C released about 70 per cent of the phosphorylated amines of the phospholipids, but had no signifi- cant effect on the CD spectrum of the protein portion of the membrane. These observations have now been extended to include a coordinated CD and pmr study of the effect of phospholipase C action on red blood cell membranes. The results indicate that the conformation of a substantial fraction of the mem- brane protein is not strongly dependent upon the physical state of the bulk of the membrane phospholipids.

AltitudeOmics: Red Blood Cell Metabolic Adaptation to High Altitude Hypoxia

Abstract: Red blood cells (RBCs) are key players in systemic oxygen transport. RBCs respond to in vitro hypoxia through the so-called oxygen-dependent metabolic regulation, which involves the competitive binding of deoxyhemoglobin and glycolytic enzymes to the N-terminal cytosolic domain of band 3. This mechanism promotes the accumulation of 2,3-DPG, stabilizing the deoxygenated state of hemoglobin, and cytosol acidification, triggering oxygen off-loading through the Bohr effect. Despite in vitro studies, in vivo adaptations to hypoxia have not yet been completely elucidated. Within the framework of the AltitudeOmics study, erythrocytes were collected from 21 healthy volunteers at sea level, after exposure to high altitude (5260 m) for 1, 7, and 16 days, and following reascent after 7 days at 1525 m. UHPLC–MS metabolomics results were correlated to physiological and athletic performance parameters. Immediate metabolic adaptations were noted as early as a few hours from ascending to >5000 m, and maintained for 16 da...

Aspects of Splenic Function in Sickle Cell Diseases

Abstract: T HE SPLEEN undergoes a definite sequence of changes in patients with sickle cell anemia (Hb SS disease.)’ During the first few months of life the spleen has normal size and function. As Hb F is replaced by Hb S in the red cells, with resultant onset of a hemolytic process, the spleen becomes palpably enlarged in many patients. Paradoxically, the functioning of the enlarged organ is defective, as indicated by its inability to remove Howell-Jolly (H-i) bodies or radiocolloids from the blood and by its inability to prevent severe bacterial infections.2’3 This early “functional” hyposplenism can be temporarily reversed by red blood cell transfusions.4 During later childhood, progressive vasoocclusion irreversibly infarcts the spleen to a siderofibrotic nubbin, a process designated autosplenectomy. Recently a noninvasive nonisotopic method has been introduced for evaluation of splenic function by examination of the circulating red cells using interference phase-contrast microscopy (Nomarski optics).5 With this technique it can be shown that about 20% of the red cells of asplenic persons contain one or more surface indentations or “pocks,” whereas fewer than 1% of the circulating red cells of normal individuals are pocked.6 The same changes have been noted in patients with Hb SS disease.7 We have studied red cells of infants and children with Hb SS disease and other sickle hemoglobinopathies using this technique in order to define

Bridging channel dendritic cells induce immunity to transfused red blood cells

Abstract: Red blood cell (RBC) transfusion is a life-saving therapeutic tool However, a major complication in transfusion recipients is the generation of antibodies against non-ABO alloantigens on donor RBCs, potentially resulting in hemolysis and renal failure Long-lived antibody responses typically require CD4+ T cell help and, in murine transfusion models, alloimmunization requires a spleen Yet, it is not known how RBC-derived antigens are presented to naive T cells in the spleen We sought to answer whether splenic dendritic cells (DCs) were essential for T cell priming to RBC alloantigens Transient deletion of conventional DCs at the time of transfusion or splenic DC preactivation before RBC transfusion abrogated T and B cell responses to allogeneic RBCs, even though transfused RBCs persisted in the circulation for weeks Although all splenic DCs phagocytosed RBCs and activated RBC-specific CD4+ T cells in vitro, only bridging channel 33D1+ DCs were required for alloimmunization in vivo In contrast, deletion of XCR1+CD8+ DCs did not alter the immune response to RBCs Our work suggests that blocking the function of one DC subset during a narrow window of time during RBC transfusion could potentially prevent the detrimental immune response that occurs in patients who require lifelong RBC transfusion support

Nanodiamonds for Medical Applications: Interaction with Blood in Vitro and in Vivo

Abstract: Nanodiamonds (ND) have emerged to be a widely-discussed nanomaterial for their applications in biological studies and for medical diagnostics and treatment. The potentials have been successfully demonstrated in cellular and tissue models in vitro. For medical applications, further in vivo studies on various applications become important. One of the most challenging possibilities of ND biomedical application is controllable drug delivery and tracing. That usually assumes ND interaction with the blood system. In this work, we study ND interaction with rat blood and analyze how the ND surface modification and coating can optimize the ND interaction with the blood. It was found that adsorption of a low concentration of ND does not affect the oxygenation state of red blood cells (RBC). The obtained in vivo results are compared to the results of in vitro studies of nanodiamond interaction with rat and human blood and blood components, such as red blood cells and blood plasma. An in vivo animal model shows ND injected in blood attach to the RBC membrane and circulate with blood for more than 30 min; and ND do not stimulate an immune response by measurement of proinflammatory cytokine TNF-α with ND injected into mice via the caudal vein. The results further confirm nanodiamonds’ safety in organisms, as well as the possibility of their application without complicating the blood’s physiological conditions.

Metabolic pathways that correlate with post-transfusion circulation of stored murine red blood cells.

Abstract: Transfusion of red blood cells is a very common inpatient procedure, with more than 1 in 70 people in the USA receiving a red blood cell transfusion annually. However, stored red blood cells are a non-uniform product, based upon donor-to-donor variation in red blood cell storage biology. While thousands of biological parameters change in red blood cells over storage, it has remained unclear which changes correlate with function of the red blood cells, as opposed to being co-incidental changes. In the current report, a murine model of red blood cell storage/transfusion is applied across 13 genetically distinct mouse strains and combined with high resolution metabolomics to identify metabolic changes that correlated with red blood cell circulation post storage. Oxidation in general, and peroxidation of lipids in particular, emerged as changes that correlated with extreme statistical significance, including generation of dicarboxylic acids and monohydroxy fatty acids. In addition, differences in anti-oxidant pathways known to regulate oxidative stress on lipid membranes were identified. Finally, metabolites were identified that differed at the time the blood was harvested, and predict how the red blood cells perform after storage, allowing the potential to screen donors at time of collection. Together, these findings map out a new landscape in understanding metabolic changes during red blood cell storage as they relate to red blood cell circulation.

Electrochemical Red Blood Cell Counting: One at a Time.

Abstract: We demonstrate that the concentration of a red blood cell solution under physiological conditions can be determined by electrochemical voltammetry. The magnitude of the oxygen reduction currents produced at an edge-plane pyrolytic graphite electrode was diagnosed analytically at concentrations suitable for a point-of-care test device. The currents could be further enhanced when the solution of red blood cells was exposed to hydrogen peroxide. We show that the enhanced signal can be used to detect red blood cells at a single entity level. The method presented relies on the catalytic activity of red blood cells towards hydrogen peroxide and on surface-induced haemolysis. Each single cell activity is expressed as current spikes decaying within a few seconds back to the background current. The frequency of such current spikes is proportional to the concentration of cells in solution.

Dynamic deformability of sickle red blood cells in microphysiological flow.

Abstract: In sickle cell disease (SCD), hemoglobin molecules polymerize intracellularly and lead to a cascade of events resulting in decreased deformability and increased adhesion of red blood cells (RBCs). Decreased deformability and increased adhesion of sickle RBCs lead to blood vessel occlusion (vaso-occlusion) in SCD patients. Here, we present a microfluidic approach integrated with a cell dimensioning algorithm to analyze dynamic deformability of adhered RBC at the single-cell level in controlled microphysiological flow. We measured and compared dynamic deformability and adhesion of healthy hemoglobin A (HbA) and homozygous sickle hemoglobin (HbS) containing RBCs in blood samples obtained from 24 subjects. We introduce a new parameter to assess deformability of RBCs: the dynamic deformability index (DDI), which is defined as the time-dependent change of the cell's aspect ratio in response to fluid flow shear stress. Our results show that DDI of HbS-containing RBCs were significantly lower compared to that of HbA-containing RBCs. Moreover, we observed subpopulations of HbS containing RBCs in terms of their dynamic deformability characteristics: deformable and non-deformable RBCs. Then, we tested blood samples from SCD patients and analyzed RBC adhesion and deformability at physiological and above physiological flow shear stresses. We observed significantly greater number of adhered non-deformable sickle RBCs than deformable sickle RBCs at flow shear stresses well above the physiological range, suggesting an interplay between dynamic deformability and increased adhesion of RBCs in vaso-occlusive events.

Red blood cell-derived microparticles: An overview

Abstract: The red blood cell (RBC) is historically the original parent cell of microparticles (MPs). In this overview, we describe the discovery and the early history of red cell-derived microparticles (RMPs) and present an overview of the evolution of RMP. We report the formation, characteristics, effects of RMP and factors which may affect RMP evaluation. The review examines RMP derived from both normal and pathologic RBC. The pathologic RBC studies include sickle cell anemia (SCA), sickle cell trait (STr), thalassemia intermedia (TI), hereditary spherocytosis (HS), hereditary elliptocytosis (HE), hereditary stomatocytosis (HSt) and glucose-6-phosphate dehydrogenase deficiency (G6PD).

Patient-specific blood rheology in sickle-cell anaemia.

Abstract: Sickle-cell anaemia (SCA) is an inherited blood disorder exhibiting heterogeneous cell morphology and abnormal rheology, especially under hypoxic conditions. By using a multiscale red blood cell (RBC) model with parameters derived from patient-specific data, we present a mesoscopic computational study of the haemodynamic and rheological characteristics of blood from SCA patients with hydroxyurea (HU) treatment (on-HU) and those without HU treatment (off-HU). We determine the shear viscosity of blood in health as well as in different states of disease. Our results suggest that treatment with HU improves or worsens the rheological characteristics of blood in SCA depending on the degree of hypoxia. However, on-HU groups always have higher levels of haematocrit-to-viscosity ratio (HVR) than off-HU groups, indicating that HU can indeed improve the oxygen transport potential of blood. Our patient-specific computational simulations suggest that the HVR level, rather than the shear viscosity of sickle RBC suspensions, may be a more reliable indicator in assessing the response to HU treatment.

Changes in blood biochemical markers before, during, and after a 2-day ultramarathon.

Abstract: We studied changes in blood markers of 18 nonprofessional, middle-aged runners of a 2-day, 130 km ultramarathon. Blood was sampled at baseline, after the goals on the first and second day, and at three time points (1, 3, and 5/6 days) after the race. Blood indices showed three patterns. First pattern indices showed essentially no changes after the two goals and after the race, including red blood cell indices, gamma-glutamyl transferase, and tumor necrosis factor-α. Second pattern markers, including the majority of indices, were elevated during the race (and also after the race for some parameters) and then returned to baseline afterward, including hemolysis/red blood cell destruction markers (indirect bilirubin) and an iron reservoir index (ferritin), muscle damage parameters (uric acid, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase), renal function markers (creatinine and blood urea nitrogen), liver injury index (alanine aminotransferase), lipid metabolism indices (free fatty acid), reactive oxygen species and inflammation parameters (white blood cells, interleukin-6, and C-reactive protein), and energy production and catecholamines (adrenaline, noradrenaline, and dopamine). Third pattern index of a lipid metabolism marker - triglyceride - decreased during the race periods and started returning to baseline from then onward. Some hormonal markers such as insulin, leptin, and adiponectin showed unique patterns. These findings appeared informative for nonprofessional athletes to know about an optimal physical activity level, duration, and total exercise for elevating physical performance and monitoring physical/mental conditioning as well as for prevention of overtraining and physical injuries.

Glycine and Folate Ameliorate Models of Congenital Sideroblastic Anemia

Abstract: Sideroblastic anemias are acquired or inherited anemias that result in a decreased ability to synthesize hemoglobin in red blood cells and result in the presence of iron deposits in the mitochondria of red blood cell precursors. A common subtype of congenital sideroblastic anemia is due to autosomal recessive mutations in the SLC25A38 gene. The current treatment for SLC25A38 congenital sideroblastic anemia is chronic blood transfusion coupled with iron chelation. The function of SLC25A38 is not known. Here we report that the SLC25A38 protein, and its yeast homolog Hem25, are mitochondrial glycine transporters required for the initiation of heme synthesis. To do so, we took advantage of the fact that mitochondrial glycine has several roles beyond the synthesis of heme, including the synthesis of folate derivatives through the glycine cleavage system. The data were consistent with Hem25 not being the sole mitochondrial glycine importer, and we identify a second SLC25 family member Ymc1, as a potential secondary mitochondrial glycine importer. Based on these findings, we observed that high levels of exogenous glycine, or 5-aminolevulinic acid (5-Ala) a metabolite downstream of Hem25 in heme biosynthetic pathway, were able to restore heme levels to normal in yeast cells lacking Hem25 function. While neither glycine nor 5-Ala could ameliorate SLC25A38 congenital sideroblastic anemia in a zebrafish model, we determined that the addition of folate with glycine was able to restore hemoglobin levels. This difference is likely due to the fact that yeast can synthesize folate, whereas in zebrafish folate is an essential vitamin that must be obtained exogenously. Given the tolerability of glycine and folate in humans, this study points to a potential novel treatment for SLC25A38 congenital sideroblastic anemia.

Canine Platelet-Rich Plasma Systems: A Prospective Analysis.

Abstract: Objective: To quantitate key parameters of the platelet rich plasma (PRP) product from five commercial canine PRP systems in healthy, adult canines. Materials and Methods: A prospective study was performed from January 2013 to April 2014. Five commercial systems were analyzed using ten healthy dogs per system.a-e Blood was obtained according to the manufacturer’s protocol for each system. The mean baseline whole blood platelet, RBC, WBC, neutrophil, monocyte, and lymphocyte concentrations were determined for each PRP system. All blood samples were processed according to the manufacturer’s protocols. The mean PRP product platelet, RBC, WBC, neutrophil, monocyte, and lymphocyte concentrations were determined for each PRP system. These values were then compared to the mean baseline values. Comparisons of mean whole blood and mean PRP product parameters were calculated using a paired t-test with significance established at p = 0.05.g Results: Platelet concentration was significantly increased for System 1 (p=0.0088) and System 3 (p<0.0001), and was significantly decreased for System 2 (p<0.0001). All five systems significantly decreased the red blood cell concentration (p<0.0001 for each system comparison). Neutrophil concentration was significantly decreased for System 2, System 3, and System 4 (p<0.0001 for each system comparison). Neutrophil concentration was significantly increased for System 5 (p=0.0089). Clinical Relevance: The systems with the highest platelet yield were System 1 and System 3. System 3 increased platelet concentration while significantly reducing the RBC and neutrophil concentrations. Further study is indicated to assess the efficacy of PRP therapy in canines, the efficacy of canine PRP systems, and the clinical applications for PRP therapy in dogs. Abbreviations: PRP: Platelet rich plasma LR-PRP: Leukocyte rich platelet rich plasma LP-PRP: Leukocyte poor platelet rich plasma ACP: autologous conditioned plasma WBC: white blood cell RBC: red blood cell

Extracellular Vesicles from Red Blood Cell Products Induce a Strong Pro-Inflammatory Host Response, Dependent on Both Numbers and Storage Duration

Abstract: Background: Transfusion of red blood cells (RBCs) is associated with adverse outcome, but the causative factor is unknown. Extracellular vesicles (EVs) have pro-inflammatory propert

A micro-scale simulation of red blood cell passage through symmetric and asymmetric bifurcated vessels.

Abstract: Blood exhibits a heterogeneous nature of hematocrit, velocity, and effective viscosity in microcapillaries. Microvascular bifurcations have a significant influence on the distribution of the blood cells and blood flow behavior. This paper presents a simulation study performed on the two-dimensional motions and deformation of multiple red blood cells in microvessels with diverging and converging bifurcations. Fluid dynamics and membrane mechanics were incorporated. Effects of cell shape, hematocrit, and deformability of the cell membrane on rheological behavior of the red blood cells and the hemodynamics have been investigated. It was shown that the blood entering the daughter branch with a higher flow rate tended to receive disproportionally more cells. The results also demonstrate that red blood cells in microvessels experienced lateral migration in the parent channel and blunted velocity profiles in both straight section and daughter branches, and this effect was influenced by the shape and the initial position of the cells, the hematocrit, and the membrane deformability. In addition, a cell free region around the tip of the confluence was observed. The simulation results are qualitatively consistent with existing experimental findings. This study may provide fundamental knowledge for a better understanding of hemodynamic behavior of micro-scale blood flow.

In vitro hemocompatibility testing: The importance of fresh blood.

Abstract: The use of unactivated blood for hemocompatibility testing is essential to obtain reliable results. Here, the authors study the influence of heparinized whole blood storage time and temperature on blood activation and evaluate the importance of initiating hemocompatibility tests within 4 h of blood collection. Blood from healthy volunteers was collected and analyzed with minimal delay, after 30 min and after 60 min of storage at room temperature, 30 or 37 °C. In addition, blood was analyzed after 1, 2, or 4 h of storage at room temperature. Platelet count, mean platelet volume, platelet binding capacity to collagen and thromboxane B2 were measured to assess platelet function, complement complex C5b-9 and elastase were measured to assess activation of the inflammatory response system, and thrombin-antithrombin III was measured to assess activation of the coagulation system. Furthermore, free hemoglobin was measured in platelet poor plasma as an indicator for red blood cell damage. The authors found that storage at 30 °C significantly increased platelet and coagulation activity after 60 min and storage at 37 °C significantly increased platelet, coagulation, and white blood cell activity after 60 min. Storage at room temperature significantly decreased platelet binding to collagen after 4 h and increased platelet activity after 1 h onward and white blood cell activity after 4 h. Their results show that short-term storage of heparinized whole blood significantly influences biomarkers over time, especially at 30 and 37 °C compared to room temperature. However, blood stored at room temperature for 4 h is also affected. In particular, platelet function and white blood cell activity are significantly influenced after 4 h of stationary storage at room temperature; therefore, the authors propose that hemocompatibility tests should be initiated well within 4 h of blood collection, preferably within 2 h.

Chronic inflammatory autoimmune disorders are a risk factor for red blood cell alloimmunization

Abstract: Fritz, A., Percy, C., Jack, A., Shanmugaratnam, K., Sobin, L., Parkin, D.M. & Whelan, S. (eds) (2013) International Classification of Diseases for Oncology, 3rd edn. World Health Organization, Geneva, Switzerland. Gidengil, C.A., Predmore, Z., Mattke, S., van Busum, K. & Kim, B. (2015) Breast implant-associated anaplastic large cell lymphoma: a systematic review. Plastic and Reconstructive Surgery, 135, 713–720. Jewell, M., Spear, S.L., Largent, J., Oefelein, M.G. & Adams, Jr, W.P. (2011) Anaplastic large T-cell lymphoma and breast implants: a review of the literature. Plastic and Reconstructive Surgery, 128, 651–661. de Jong, D., Vasmel, W.L., de Boer, J.P., Verhave, G., Barbe, E., Casparie, M.K. & van Leeuwen, F.E. (2008) Anaplastic large-cell lymphoma in women with breast implants. Journal of the American Medical Association, 300, 2030–2035. Lipworth, L., Tarone, R. & McLaughlin, J. (2009) Breast implants and lymphoma risk: a review of the epidemiologic evidence through 2008. Plastic and Reconstructive Surgery, 123, 790–793. Spear, S.L., Largent, J., Kaplowitz, H., Kaplan, H.M., Oefelein, M.G. & Beddingfield, F. (2010) Occurrence of anaplastic large cell lymphoma (ALCL) among large multi-center prospective clinical studies of breast implant patients. Plastic and Reconstructive Surgery, 126, 68. Thompson, P.A. & Prince, H.M. (2013) Breast implant-associated anaplastic large cell lymphoma: a systematic review of the literature and mini-meta analysis. Current Hematologic Malignancy Reports, 8, 196–210. United States Food and Drug Administration. Anaplastic large cell lymphoma (ALCL) in women with breast implants: preliminary FDA findings and analyses. 2011. http://www.fda.gov/ MedicalDevices/ProductsandMedicalProcedures/ ImplantsandProsthetics/BreastImplants/ ucm239996.htm Vase, M.O., Friis, S., Bautz, A., Bendix, K., Sorensen, H.T. & d’Amore, F. (2013) Breast implants and anaplastic large-cell lymphoma: a Danish population-based cohort study. Cancer Epidemiology, Biomarkers & Prevention, 22, 2126–2129. Wang, S.S., Flowers, C.R., Kadin, M.E., Chang, E.T., Hughes, A.M., Ansell, S.M., Fedlman, A.L., Lightfoot, T., Boffetta, P., Melbye, M., Lan, Q., Sampson, J.N., Morton, L.M., Zhang, Y. & Weisenburger, D.D. (2014) Medical history, lifestyle, family history, and occupational risk factors for peripheral T-cell lymphomas: the InterLymph Non-Hodgkin Lymphoma Subtypes Project. Journal of the National Cancer Institute Monographs, 2014, 66–75.

The endothelial glycocalyx promotes homogenous blood flow distribution within the microvasculature

Abstract: Many common diseases involve impaired tissue perfusion, and heterogeneous distribution of blood flow in the microvasculature contributes to this pathology. The physiological mechanisms regulating homogeneity/heterogeneity of microvascular perfusion are presently unknown. Using established empirical formulations for blood viscosity modeling in vivo (blood vessels) and in vitro (glass tubes), we showed that the in vivo formulation predicts more homogenous perfusion of microvascular networks at the arteriolar and capillary levels. Next, we showed that the more homogeneous blood flow under simulated in vivo conditions can be explained by changes in red blood cell interactions with the vessel wall. Finally, we demonstrated that the presence of a space-filling, semipermeable layer (such as the endothelial glycocalyx) at the vessel wall can account for the changes of red blood cell interactions with the vessel wall that promote homogenous microvascular perfusion. Collectively, our results indicate that the mechanical properties of the endothelial glycocalyx promote homogeneous microvascular perfusion. Preservation or restoration of normal glycocalyx properties may be a viable strategy for improving tissue perfusion in a variety of diseases.

The Role of Physical Stabilization in Whole Blood Preservation

Abstract: The rapid degradation of blood ex vivo imposes logistical limitations on the utilization of blood-borne cells in medical diagnostics and scientific investigations. A fundamental but overlooked aspect in the storage of this fluid tissue is blood settling, which induces physical stress and compaction, aggregates blood cells, and causes collateral damage due to leukocyte activation. Here we show that the polymer Ficoll 70 kDa stabilized blood samples and prevented blood settling over the course of 72 hours, primarily by inhibiting depletion-mediated red blood cell aggregation. Physical stabilization decreased echinocyte formation, improved leukocyte viability, and inhibited the release of neutrophil elastase--a marker of neutrophil extracellular trap formation. In addition, Ficoll-stabilized blood was compatible with common leukocyte enrichment techniques including red blood cell lysis and immunomagnetic purification. This study showed for the first time that blood settling can be prevented using polymers and has implications in diagnostics.

Sevuparin binds to multiple adhesive ligands and reduces sickle red blood cell-induced vaso-occlusion

Abstract: Sevuparin is a novel drug candidate in phase II development as a treatment for vaso-occlusive crises (VOC) in patients with sickle cell disease (SCD). As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Here, we demonstrate that sevuparin inhibits the adhesion of human sickle red blood cells (SS-RBCs) to stimulated cultured endothelial cells in vitro. Importantly, sevuparin prevents vaso-occlusion and normalizes blood flow in an in vivo mouse model of SCD vaso-occlusion. Analyses by surface plasmon resonance (SPR) and fluorescence correlation spectroscopy (FCS) demonstrate that sevuparin binds to P- and L-selectins, thrombospondin, fibronectin and von Willebrand factor, all of which are thought to contribute to vaso-occlusion in SCD. Despite low anticoagulation activity, sevuparin has anti-adhesive efficacy similar to the low molecular weight heparin tinzaparin both in vitro and in vivo. These results suggest that the anti-adhesive properties rather than the anticoagulant effects of heparinoids are critical for the treatment of vaso-occlusion in SCD. Therefore, sevuparin is now being evaluated in SCD patients hospitalized for treatment of VOC.

Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

Abstract: Iron deficiency, the most common health problem in the world, has required a blood test for diagnosis. Here, the authors show that iron deficiency can be detected non-invasively and quickly by measuring the fluorescence of red blood cell zinc protoporphyrin in the microcirculation of the lip.

A Novel Variant in CMAH Is Associated with Blood Type AB in Ragdoll Cats.

Abstract: The enzyme cytidine monophospho-N-acetylneuraminic acid hydroxylase is associated with the production of sialic acids on cat red blood cells. The cat has one major blood group with three serotypes; the most common blood type A being dominant to type B. A third rare blood type is known as AB and has an unclear mode of inheritance. Cat blood type antigens are defined, with N-glycolylneuraminic acid being associated with type A and N-acetylneuraminic acid with type B. Blood type AB is serologically characterized by agglutination using typing reagents directed against both A and B epitopes. While a genetic characterization of blood type B has been achieved, the rare type AB serotype remains genetically uncharacterized. A genome-wide association study in Ragdoll cats (22 cases and 15 controls) detected a significant association between blood type AB and SNPs on cat chromosome B2, with the most highly associated SNP being at position 4,487,432 near the candidate gene cytidine monophospho-N-acetylneuraminic acid hydroxylase. A novel variant, c.364C>T, was identified that is highly associated with blood type AB in Ragdoll cats and, to a lesser degree, with type AB in random bred cats. The newly identified variant is probably linked with blood type AB in Ragdoll cats, and is associated with the expression of both antigens (N-glycolylneuraminic acid and N-acetylneuraminic acid) on the red blood cell membrane. Other variants, not identified by this work, are likely to be associated with blood type AB in other breeds of cat.