Donor-specific individuality of red blood cell performance during storage is partly a function of serum uric acid levels.

BACKGROUND: Previous investigations in leukoreduced units of red blood cells (RBCs) in mannitol additive solution revealed the close association of uric acid (UA) levels in vivo with the susceptibility of RBCs to storage lesion markers. In this study, we examined whether UA has a similar correlation with the capability of RBCs to cope with the oxidative provocations of storage under different conditions, namely, in CPDA-1 and in the absence of leukoreduction. STUDY DESIGN AND METHODS: The UA-dependent antioxidant capacity of the supernatant was measured in nonleukoreduced units of RBCs in CPDA (n = 47). The possible effect of UA variability on the storage lesion profile was assessed by monitoring several physiologic properties of RBCs and supernatant, including cell shape, reactive oxygen species, and size distribution of extracellular vesicles, in units exhibiting the lowest or highest levels of UA activity (n = 16) among donors, throughout the storage period. RESULTS: In stored RBC units, the UA-dependent antioxidant activity of the supernatant declined as a function of storage duration but always in strong relation to the UA levels in fresh blood. Contrary to units of poor-UA activity, RBCs with the highest levels of UA activity exhibited better profile of calcium- and oxidative stress-driven modifications, including a significant decrease in the percentages of spherocytes and of 100- to 300-nm-sized vesicles, typically associated with the exovesiculation of stored RBCs. CONCLUSION: The antioxidant activity of UA is associated with donor-specific differences in the performance of RBCs under storage in nonleukoreduced CPDA units.

Characterizing pathology in erythrocytes using morphological and biophysical membrane properties: Relation to impaired hemorheology and cardiovascular function in rheumatoid arthritis.

The inflammatory burden of the complex rheumatoid arthritis (RA) disease affects several organ-systems, including rheological properties of blood and its formed elements. Red blood cells (RBCs) are constantly exposed to circulating dysregulated inflammatory molecules that are co-transported within the vasculature; and their membranes may be particularly vulnerable to the accompanying oxidative stress. In the current study, we investigate biophysical and ultrastructural characteristics of RBCs obtained from a cohort of patients using atomic force microscopy (AFM), scanning electron microscopy (SEM) and confocal microscopy (CM). Statistical analyses of AFM data showed that RA RBCs possessed significantly reduced membrane elasticity relative to that of RBCs from healthy individuals (P-value <0.0001). SEM imaging of RA RBCs revealed increased anisocytes and poikilocytes. Poikilocytes included knizocytes, stomatocytes, dacryocytes, irregularly contracted cells, and knot cells. CM imaging of several RA RBCs, spectrin, and band 3 protein networks portrayed the similar morphological profiles. Analyses of CM images confirmed changes to distribution of band-3 skeletal protein, a protein critical for gaseous exchange functions of the RBC and preventing membrane surface loss. Decreased membrane deformability impairs the RBC's capacity to adequately adapt its shape to navigate blood vessels, especially microvasculature, and this decrease is also reflected in the cell's morphology. Changes to morphology and deformability may also indicate loss of functional domains and/or pathological protein and lipid associations. These findings suggest that RA disease and/or its concomitant factors impact on the RBC and its membrane integrity with potential for exacerbating pathological cellular function, hemorheology, and cardiovascular function.

A rare form of anemia in systemic lupus erythematosus.

Mechanisms responsible for anemia in systemic lupus erythematosus (SLE) can be immune or non-immune. A 27-year-old previously healthy woman was admitted with echymotic patches over the lower limbs for six months, multiple joint pain and fatigue for 2 months. She had severe pallor and multiple echymotic patches over the lower limbs. She was diagnosed with SLE with pernicious anemia and iron deficiency anemia. The rare association of SLE with pernicious anemia was reported previously in few patients. Treatment of SLE along with B12 supplementation is necessary for such patients. Since etiology for anemia in SLE can be of various kinds, a detailed workup for identifying the underlying mechanism is necessary.

Association of abnormal erythrocyte morphology with oxidative stress and inflammation in metabolic syndrome.

In carrying out their role of free radical scavenging, erythrocytes become damaged due to oxidation of membrane lipids and proteins. Such damage may change the morphology of the erythrocytes. The present study aims to demonstrate change in erythrocyte morphology in MetS and associate the changes with increased oxidative stress and inflammation that were shown in our recent study. One hundred participants were recruited from a rural town of Australia. Whole blood viscosity, erythrocyte aggregation, erythrocyte deformability, lipid profile and blood sugar level, oxidative stress markers (erythrocyte reduced glutathione, superoxide dismutase, urinary isoprostanes) and inflammatory markers (high sensitivity C-reactive protein) were measured. Erythrocyte morphological study was performed by scanning electron microscopy. Recruited participants were classified into MetS and non-MetS following the National Cholesterol Education Program Adult Treatment Panel III definition. Data were analyzed by IBM SPSS 20 software. The mean percentages of biconcave cells were decreased whereas acanthocytes, stomatocytes and echinocytes were increased in MetS group compared to healthy controls. Morphologically abnormal erythrocytes were significantly correlated with oxidative stress and chronic inflammation markers. Free radicals generated in increased concentration in MetS seem to damage erythrocyte changing its morphology which possibly could affect other hemorheological parameters.

Washing stored red blood cells in an albumin solution improves their morphologic and hemorheologic properties.

BACKGROUND: Prolonged storage of red blood cells (RBCs) leads to storage lesions, which may impair clinical outcomes after transfusion. A hallmark of storage lesions is progressive echinocytic shape transformation, which can be partially reversed by washing in albumin solutions. Here we have investigated the impact of this shape recovery on biorheologic variables. STUDY DESIGN AND METHODS: RBCs stored hypothermically for 6 to 7 weeks were washed in a 1% human serum albumin (HSA) solution. RBC deformability was measured with osmotic gradient ektacytometry. The viscosity of RBC suspensions was measured with a Couette-type viscometer. The flow behavior of RBCs suspended at 40% hematocrit was tested with an artificial microvascular network (AMVN). RESULTS: Washing in 1% albumin reduced higher degrees of echinocytes and increased the frequency of discocytes, thereby shifting the morphologic index toward discocytosis. Washing also reduced RBC swelling. This shape recovery was not seen after washing in saline, buffer, or plasma. RBC shape normalization did not improve cell deformability measured by ektacytometry, but it tended to decrease suspension viscosities at low shear rates and improved the perfusion of an AMVN. CONCLUSIONS: Washing of stored RBCs in a 1% HSA solution specifically reduces echinocytosis, and this shape recovery has a beneficial effect on microvascular perfusion in vitro. Washing in 1% albumin may represent a new approach to improving the quality of stored RBCs and thus potentially reducing the likelihood of adverse clinical outcomes associated with transfusion of blood stored for longer periods of time.

Specific macrothrombocytopenia/hemolytic anemia associated with sitosterolemia.

Sitosterolemia (phytosterolemia) is a rare inherited sterol storage disorder, characterized by significantly elevated plasma levels of plant sterols. The clinical features of sitosterolemia are xanthomas, premature atherosclerosis, arthritis, and, occasionally, liver function impair and hematologic abnormalities. This disorder is caused by mutations of ABCG5/ABCG8 genes. We report here the clinical, laboratory, and molecular genetic features of 13 patients with sitosterolemia from eight unrelated families who had specific hematologic problems of macrothrombocytopenia, hemolytic anemia, and splenomegaly besides the major clinical manifestations. The peripheral blood films showed some unique features: large platelets surrounded by a circle of vacuoles, and various abnormal erythrocyte shapes, especially stomatocyte. According to these distinct changes of blood cell morphology, we identified two sitosterolemia patients who lacked the classical clinical phenomena. All the patients had been misdiagnosed with immune thrombocytopenia (ITP), Evans syndrome, or secondary ITP with delay being 28.8 years between symptom onset and correct diagnosis. These results indicate that sitosterolemia is certainly not as rare as originally thought. The phenomena of macrothrombocytopenia/hemolysis might represent a new platelet disorder. Plasma plant sterols and ABCG5/ABCG8 genes should be analyzed when such hematologic abnormalities are unexplained.

Atypical erythrocytes and platelets in a patient with a pro-thrombin mutation.

Prothrombin mutation G20210A, anti-phospholipid syndrome as well as iron overload has previously been shown to cause thrombotic events. The main reason for this is the involvement of these anomalies in causing hypercoagulability of the coagulation system, which frequently leads to venous and arterial thrombotic events. We report the case of a 37-year-old white female with prothrombin mutation G20210A, anti-phospholipid syndrome, as well as an increased serum ferritin level, who experienced two transient ischemic attacks and suffers from regular amaurosis fugax. We present an ultrastructural depiction of erythrocytes, platelets, and the fibrin network, to explain the clinical manifestations of the thrombotic state seen in this patient.

Tropomodulin 1-null mice have a mild spherocytic elliptocytosis with appearance of tropomodulin 3 in red blood cells and disruption of the membrane skeleton.

The short actin filaments in the red blood cell (RBC) membrane skeleton are capped at their pointed ends by tropomodulin 1 (Tmod1) and coated with tropomyosin (TM) along their length. Tmod1-TM control of actin filament length is hypothesized to regulate spectrin-actin lattice organization and membrane stability. We used a Tmod1 knockout mouse to investigate the in vivo role of Tmod1 in the RBC membrane skeleton. Western blots of Tmod1-null RBCs confirm the absence of Tmod1 and show the presence of Tmod3, which is normally not present in RBCs. Tmod3 is present at only one-fifth levels of Tmod1 present on wild-type membranes, but levels of actin, TMs, adducins, and other membrane skeleton proteins remain unchanged. Electron microscopy shows that actin filament lengths are more variable with spectrin-actin lattices displaying abnormally large and more variable pore sizes. Tmod1-null mice display a mild anemia with features resembling hereditary spherocytic elliptocytosis, including decreased RBC mean corpuscular volume, cellular dehydration, increased osmotic fragility, reduced deformability, and heterogeneity in osmotic ektacytometry. Insufficient capping of actin filaments by Tmod3 may allow greater actin dynamics at pointed ends, resulting in filament length redistribution, leading to irregular and attenuated spectrin-actin lattice connectivity, and concomitant RBC membrane instability.

Hyposplenism: comparison of different methods for determining splenic function.

Asplenic patients are at risk for pneumococcal sepsis. Patients with hyposplenic function, such as associated with sickle cell disease (SCD), are also at risk. However, tests to assess splenic function are either unavailable or lacking standardization. The aim of this study was to compare different methods for determining splenic function. Eighteen patients with SCD (i.e., 10 heterozygous (SC) and 8 homozygous (SS) SCD patients), and eight splenectomized patients were compared to 10 controls. All subjects underwent spleen scintigraphy, after which functional splenic volumes (FSV) were calculated. FSV was compared to immunological function and B cell-subsets, as well as phagocytic function represented by the presence of Howell Jolly bodies (HJB) and percentages of pitted red cells (PIT). Heterozygous SCD (SC) patients had increased splenic volumes, but diminished FSV, homozygous SCD (SS) patients were asplenic. Splenectomized and SS patients had a strongly reduced phagocytic and immunological function. SC patients had reduced anti-polysaccharide responses without an increase in PIT. FSV correlated significantly with phagocytic and immunological function. HJB were indicative of splenic dysfunction, HJB absence was not indicative of normal functioning splenic tissue. Although visualizing HJB is methodologically advantageous to PIT, both are valid biomarkers of splenic dysfunction. The amount of non-switched memory B cells is strongly correlated to FSV.