Synthesis of Artificial Models of Sickle Red Cells

1987 ◽  
Vol 110 ◽  
Author(s):  
Roderick D. Macgregor ◽  
Noel Taylor ◽  
Bertram Lubin ◽  
C. Anthony Hunt
Keyword(s):  
Lipid Bilayer ◽  
Bilayer Membrane ◽  
Cell System ◽  
Red Cells ◽  
Primary Role ◽  
Red Cell ◽  
Before And After ◽  
Synthetic Cells

AbstractThe primary role of a red cell substitute is to deliver oxygen to cells eitherin vivo or in vitro. It seems reasonable to mimic evolution, which solved the problem of oxygen delivery in many species by encapsulating oxygen carrying proteins in cell-sized delivery systems. We have successfully synthesized and tested an artificial red cell (Neohemocytes: see Science 230, 1165, 1985). How many properties or functions of red cells can one mimic synthetically? Can these synthetic cells serve as useful models? Here we report the first successful synthesis of an artificial model sickle cell. No reproducible, model cell system was previously available for research. A procedure identical to that used to prepare normal neohemocytes (NHC) was employed using sickle hemoglobin (HbS). The starting material was O2or CO liganded HbS at a concentration of approximately 15g% in a 30 mOsm phosphate buffer; this solution was kept ultrahypotonic until the final stage of the process. The lipid bilayer membrane was formed during a prolonged adjustment of the osmolality to 300 mOsm. The final step was removal of unencapsulated HbS. Sickle NHC were examined in parallel with normal (HbA containing) NHC by scanning and thin section electron microscopy before and after deoxygenation. These synthetic cells do sickle! Some look remarkably like red blood cells, only much smaller. Our data suggests that polymerization of the HbS within sickle NHC may be initiated by a different mechanism than the polymerization of purified solutions of HbS. The typical lipid bilayer seen in HbA containing NBC was essentially absent in the sickle NHC: similar results have been reported for irreversibly sickled red cells. Sickle NHC thus have remarkable potential to function as model sickle cells.

LACK OF EFFECT OF CORTICOSTEROIDS ON THE IN VIVO DISAPPEARANCE OF SULFHYDRYL-INHIBITED AND ANTIBODY-COATED ERYTHROCYTES

1964 ◽  
Vol 47 (3_Suppl) ◽  
pp. S28-S36
Author(s):  
Kailash N. Agarwal
Keyword(s):  
Red Cells ◽  
List Type ◽  
Red Cell

ABSTRACT Red cells were incubated in vitro with sulfhydryl inhibitors and Rhantibody with and without prior incubation with prednisolone-hemisuccinate. These erythrocytes were labelled with Cr51 and P32 and their disappearance in vivo after autotransfusion was measured. Prior incubation with prednisolone-hemisuccinate had no effect on the rate of red cell disappearance. The disappearance of the cells was shown to take place without appreciable intravascular destruction.

scholarly journals Effect of oxalate and malonate on red cell metabolism

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1389-1393
Author(s):  
E Beutler ◽  
L Forman ◽  
C West
Keyword(s):  
Pyruvate Kinase ◽  
Cell Metabolism ◽  
Inhibitory Effect ◽  
Red Cells ◽  
Red Cell ◽  
Acid Analogue ◽  
2,3 Dpg

The addition of oxalate to blood stored in Citrate-phosphate-dextrose (CPD) produces a marked improvement in 2,3-diphosphoglycerate (2,3-DPG) preservation; an increase in 2,3-DPG levels can also be documented in short-term incubation studies. Oxalate is a potent in vitro inhibitor of red cell lactate dehydrogenase, monophosphoglycerate mutase, and pyruvate kinase (PK). In the presence of fructose 1,6-diphosphate the latter inhibitory effect is competitive with phospho(enol)pyruvate (PEP). Determination of the levels of intermediate compounds in red cells incubated with oxalate suggest the presence of inhibition at the PK step, indicating that this is the site of oxalate action. Apparent inhibition at the glyceraldehyde phosphate dehydrogenase step is apparently due to an increase in the NADH/NAD ratio. Oxalate had no effect on the in vivo viability of rabbit red cells stored in CPD preservatives for 21 days. Greater understanding of the toxicity of oxalate is required before it can be considered suitable as a component of preservative media, but appreciation of the mechanism by which it affects 2,3-DPG levels may be important in design of other blood additives. Malonate, the 3-carbon dicarboxylic acid analogue of oxalate late did not inhibit pyruvate kinase nor affect 2,3-DPG levels.

scholarly journals The relationship between in vivo generated hemoglobin skeletal protein complex and increased red cell membrane rigidity

Blood ◽  
1988 ◽  
Vol 71 (5) ◽  
pp. 1427-1431 ◽  
Author(s):  
N Fortier ◽  
LM Snyder ◽  
F Garver ◽  
C Kiefer ◽  
J McKenney ◽  
...  
Keyword(s):  
Protein Complex ◽  
Sodium Dodecyl ◽  
Red Cells ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Cellular Dehydration ◽  
Thalassemia Minor ◽  
Membrane Rigidity

Abstract In vitro induced oxidative damage to normal human RBCs has previously been shown to result in increased membrane rigidity as a consequence of the generation of a protein complex between hemoglobin and spectrin. In order to determine if in vivo generated hemoglobin-spectrin complexes may play a role in increased membrane rigidity of certain pathologic red cells, we measured both these parameters in membranes prepared from hereditary xerocytosis (Hx), sickle cell disease (Sc), and red cells from thalassemia minor (beta thal). Membranes were prepared from density-fractionated red cells, and membrane deformability was measured using an ektacytometer. Hemoglobin-spectrin complex was determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel analysis, as well as by Western blot analysis using a monoclonal antibody against the beta- subunit of hemoglobin. For these three types of pathologic red cells, progressive cellular dehydration was associated with increased membrane rigidity and increased content of hemoglobin-spectrin complex. Moreover, the increase in membrane rigidity appeared to be directly related to the quantity of hemoglobin-spectrin complex associated with the membrane. Our findings imply that hemoglobin-spectrin complex is generated in vivo, and this in turn results in increased membrane rigidity of certain pathologic red cells. The data further suggest that oxidative crosslinking may play an important role in the pathophysiology of certain red cell disorders.

scholarly journals Reticulocyte Survival in Sickle Cell Anemia: Effect of Cyanate

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 733-739 ◽  
Author(s):  
Blanche P. Alter ◽  
Yuet Wai Kan ◽  
David G. Nathan
Keyword(s):  
Cell Survival ◽  
Sickle Cell ◽  
Fetal Hemoglobin ◽  
Red Cells ◽  
Red Cell ◽  
Hemoglobin Molecule ◽  
Red Cell Survival ◽  
And Control

Abstract Cyanate prevents sickling in vitro and apparently prolongs the survival of 51Cr-tagged sickle erythrocytes in vivo. Cautious interpretation is required because the effects of cyanate on 51Cr binding to sickle and fetal hemoglobin-containing red cells are unknown, and comparison of the effect of cyanate on sickle red cell survival to control red cell survival must be performed sequentially. We have studied the survival of sickle reticulocytes utilizing radioactive amino acids that are incorporated into hemoglobin. Two informed adult patients with sickle cell disease were studied. In each study, two 50-ml samples of blood were incubated separately with 14C- and 3H-leucine for 2 hr, after which 50 mM cyanate was added to one aliquot for 1 hr. The cells were then washed and reinfused. Frequent venous samples were obtained, and the specific activities of 14C and 3H in the hemoglobin were followed. The t ½ of the carbamylated cells was tripled, but remained below normal. This method provides a generally useful measurement of the influence of drugs bound to red cells on reticulocyte lifespan. The labels are incorporated into the hemoglobin molecule of the reticulocyte, and simultaneous comparison of the survivals of the same cohort of drug-treated and control cells is achieved.

scholarly journals Effect of oxalate and malonate on red cell metabolism

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1389-1393 ◽  
Author(s):  
E Beutler ◽  
L Forman ◽  
C West
Keyword(s):  
Pyruvate Kinase ◽  
Cell Metabolism ◽  
Inhibitory Effect ◽  
Red Cells ◽  
Red Cell ◽  
Acid Analogue ◽  
2,3 Dpg

Abstract The addition of oxalate to blood stored in Citrate-phosphate-dextrose (CPD) produces a marked improvement in 2,3-diphosphoglycerate (2,3-DPG) preservation; an increase in 2,3-DPG levels can also be documented in short-term incubation studies. Oxalate is a potent in vitro inhibitor of red cell lactate dehydrogenase, monophosphoglycerate mutase, and pyruvate kinase (PK). In the presence of fructose 1,6-diphosphate the latter inhibitory effect is competitive with phospho(enol)pyruvate (PEP). Determination of the levels of intermediate compounds in red cells incubated with oxalate suggest the presence of inhibition at the PK step, indicating that this is the site of oxalate action. Apparent inhibition at the glyceraldehyde phosphate dehydrogenase step is apparently due to an increase in the NADH/NAD ratio. Oxalate had no effect on the in vivo viability of rabbit red cells stored in CPD preservatives for 21 days. Greater understanding of the toxicity of oxalate is required before it can be considered suitable as a component of preservative media, but appreciation of the mechanism by which it affects 2,3-DPG levels may be important in design of other blood additives. Malonate, the 3-carbon dicarboxylic acid analogue of oxalate late did not inhibit pyruvate kinase nor affect 2,3-DPG levels.

scholarly journals Near-normal circulatory survival of rabbit red cells exposed to high levels of Ca and ionophore in vitro

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 220-223 ◽  
Author(s):  
RM Bookchin ◽  
EF Jr Roth ◽  
VL Lew
Keyword(s):  
Adenosine Triphosphate ◽  
Indirect Evidence ◽  
Red Cells ◽  
Ionophore A23187 ◽  
Red Cell ◽  
L Cells

Abstract The belief is widely held, on the basis of indirect evidence, that a substantial, even brief elevation of red cell Ca content must result in a marked shortening of circulatory survival. To test this notion directly, we exposed rabbit red cells in vitro to the ionophore A23187 and Ca so as to produce sustained uniform cell Ca levels of 40 to 360 mumol/L cells for one to 60 minutes, and compared the survival of the Ca-loaded cells in vivo with that of ionophore-treated controls, simultaneously, in the same rabbits. Despite marked reductions in cell adenosine triphosphate and dehydration of the Ca-exposed cells prior to reinfusion, the majority of cells, all of which had experienced these high cytoplasmic Ca levels, showed normal or near-normal survival in the circulation.

scholarly journals Some Interrelationships of Blood and the Fava Bean Principle in Vitro

Blood ◽  
1952 ◽  
Vol 7 (7) ◽  
pp. 721-728 ◽  
Author(s):  
WILLIAM P. CREGER ◽  
HOUGHTON GIFFORD
Keyword(s):  
Animal Species ◽  
Gamma Globulin ◽  
Test Tube ◽  
Red Cells ◽  
Red Cell ◽  
Fava Bean ◽  
Increased Susceptibility ◽  
Human Red Cells

Abstract 1. Saline suspensions of human red cells, as well as those of several animal species, were agglutinated by normal saline extracts of the Fava bean. 2. This agglutination was potentiated in titer 100-fold in a medium of 10 per cent acacia, as a diluent. 3. The inhibition of the hemagglutination action of the Fava bean extract by human serum was apparently attributable to the gamma globulin fraction. 4. The Fava bean principle could be transferred from cell to cell, as shown by heat-elution and acacia technics. 5. Fava-sensitized red cells did not exhibit increased susceptibility in the test tube to complement, hemolysin, or osmotic or mechanical fragility. 6. The mechanism of in vivo red cell destruction in Favism is as yet unknown, but a special immunologic susceptibility to the action of the bean’s principle is suspected in certain persons. 7. It is suggested that the relation of acacia to Fava-sensitized red cells may form the basis of a diagnostic test for Favism in the early, acute stages of the disease.

scholarly journals Energy metabolism in trout red cells: consequences of adrenergic stimulation in vivo and in vitro

1989 ◽  
Vol 143 (1) ◽  
pp. 133-147 ◽  
Author(s):  
R. A. Ferguson ◽  
B. L. Tufts ◽  
R. G. Boutilier
Keyword(s):  
Ph Regulation ◽  
Red Cells ◽  
Red Cell ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Extracellular Acidosis ◽  
Metabolic Functions ◽  
The Face

beta-Adrenergic stimulation of salmonid red cells results in a rapid decrease (within 5 min) in the nucleotide triphosphate:haemoglobin ratio (NTP:Hb), which is thereafter maintained at a constant level, presumably through increased ATP turnover via matched aerobic metabolism and energy-consuming processes. Addition of the beta-adrenergic agonist isoproterenol to rainbow trout red cells in vitro leads to a rise in intracellular pH (pHi), a corresponding decrease in extracellular pH (pHe) and an increase in red cell oxygen consumption (MO2). Moreover, the extent to which red cell pHi is maintained constant in the face of an acute extracellular acidosis in vitro or in vivo is proportional to the adrenergically stimulated increase in red cell MO2. In the absence of oxygen, these red cells remain capable of pH regulation, but cannot maintain NTP:Hb constant. As a result, membrane and metabolic functions become uncoupled in the stimulated deoxygenated cells.

scholarly journals The Removal of in Vitro Damaged Erythrocytes from the Circulation of Normal and Splenectomized Rats

Blood ◽  
1965 ◽  
Vol 26 (1) ◽  
pp. 49-62 ◽  
Author(s):  
JOHN E. ULTMANN ◽  
CLARA S. GORDON
Keyword(s):  
Life Span ◽  
Osmotic Fragility ◽  
Reticuloendothelial System ◽  
Red Cells ◽  
In Vitro Tests ◽  
Red Cell ◽  
Cell Integrity ◽  
Prolonged Incubation

Abstract The in vitro alterations and in vivo fate of erythrocytes treated with N-ethylmaleimide or subjected to prolonged incubation were studied in normal and splenectomized rats. Minimal injury (20 µM NEM/ml. RBC) resulted in red cells with decreased osmotic fragility and increased plasticity; however, mechanical fragility was significantly increased. These cells were removed with a half-time of 78 minutes, mainly by splenic sequestration, and splenectomy prolonged their life span. Incubation at 37 C. for 21 hours produced erythrocytes with increased osmotic and mechanical fragility and decreased plasticity. Erythrocyte clearance was more rapid (T½ = 59 minutes), with spleen and liver removing approximately an equal number of cells and splenectomy having little effect on red cell life span. With severe injury (40 µM NEM/ml. RBC), all three in vitro measurements showed marked alterations, red cell removal was rapid (T½ = 35 minutes), mainly by hepatic sequestration, and clearance was unaffected by splenectomy. The present studies have shown that chemical injury or prolonged incubation lead to profound changes in in vitro tests of red cell integrity, the mechanical fragility predicting most closely the subsequent in vivo events. Although the entire reticuloendothelial system appears to participate in red cell removal, the spleen and liver are the major sites of sequestration in the rat. The splenic removal predominates with minimally injured cells, hepatic removal with moderately and severely altered cells. The type of injury appears to be of less significance than the degree of injury of the red cells.

Red Cell Properties In Haemostasis

1981 ◽  
Author(s):  
G M Housley ◽  
G V R Born
Keyword(s):  
Red Cells ◽  
Red Cell ◽  
Cell Deformability ◽  
Red Cell Deformability ◽  
Initial Flow ◽  
Red Cell Membranes ◽  
New Hypothesis ◽  
Platelets Function

Earlier observations of ours have suggested that, under in vitro conditions resembling those under which platelets function haemostatically in vivo, their activation is promoted by the red cells. Seme of the evidence suggested that this is through limited haemolysis with release of ADP. However, newly determined time relationships make this uncertain. Could red cells provide ADP without haemolysis?Crtheir flow properties affect the process more? To analyse the problem, we are determining dependence of red cell deformability on membrane constitution; and release of haemoglobin and adeninenucleotides under different conditions. Ten percent human red cell suspensions in physiological salines flow under constant pressures through 2, 3, 4 and 5 pm micropore filters, the flow rate measured continuously with an electronic balance. Initial flow rates are increased by fluidising agents, eg. ethanol, and decreased by agents with opposite effect. Our results are consistent with the new hypothesis of S.J. Singer on the mode of action of amphipathic agents, such as chlorpromazine, on red cell membranes.

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