scholarly journals Vaso-occlusion by sickle cells: evidence for selective trapping of dense red cells

Blood ◽  
1986 ◽  
Vol 68 (5) ◽  
pp. 1162-1166 ◽  
Author(s):  
DK Kaul ◽  
ME Fabry ◽  
RL Nagel
Keyword(s):  
Density Gradient ◽  
Sickle Cell ◽  
Morphological Analysis ◽  
Microvascular Obstruction ◽  
Perfusion Pressure ◽  
Peripheral Resistance ◽  
Red Cells ◽  
Arterial Perfusion ◽  
Sickle Cells ◽  
Sickle Cell Crisis

We have characterized the type of red cells from sickle cell patients that were trapped in the course of sickle-cell vaso-occlusion. In addition, the perfusion conditions (arterial perfusion pressure [Pa] and oxygen tension [PO2]) leading to experimentally induced vaso- occlusion in the artificially perfused, innervated mesocecum microvascular preparation were determined. Microvascular obstruction was induced by decrease in Pa; the lower the Pa, the greater the peripheral resistance as well as the extent of obstruction. The cells involved in the obstruction were recovered by vasodilation (secondary to denervation) and increase in Pa. Densitometric analysis of density gradient-separated infused and trapped cells was supplemented with morphological analysis to ascertain the involvement of density classes as well as morphological types seen in oxy and deoxy sickle blood. The trapping phenomenon was sensitive to PO2. Percentage of densest gradient classes, ie, fraction 3 (F3; mainly dense unsicklable SS discocytes [USDs]) and fraction 4 (F4; irreversibly sickled cells [ISCs] and the densest discocytes), showed a significant increase in trapping when perfusion was switched from oxy to deoxy perfusate. Morphological analysis revealed that unsicklable SS discocytes are more effectively trapped when deoxygenated. The deoxygenation of infused cells did not further change the percentage of ISCs trapped, suggesting that ISCs are equally capable of sequestration in the oxy and the deoxy states. The venous effluent showed a selective and significant depletion of dense cells (F4) and ISC counts at all Pa. We conclude that the progressive obstruction of the microcirculation by sickle cells involves selective sequestration of the densest classes of cells and that this mechanism might explain their partial disappearance during painful sickle cell crisis.

scholarly journals Vaso-occlusion by sickle cells: evidence for selective trapping of dense red cells

Blood ◽  
1986 ◽  
Vol 68 (5) ◽  
pp. 1162-1166 ◽  
Author(s):  
DK Kaul ◽  
ME Fabry ◽  
RL Nagel
Keyword(s):  
Density Gradient ◽  
Sickle Cell ◽  
Morphological Analysis ◽  
Microvascular Obstruction ◽  
Perfusion Pressure ◽  
Peripheral Resistance ◽  
Red Cells ◽  
Arterial Perfusion ◽  
Sickle Cells ◽  
Sickle Cell Crisis

Abstract We have characterized the type of red cells from sickle cell patients that were trapped in the course of sickle-cell vaso-occlusion. In addition, the perfusion conditions (arterial perfusion pressure [Pa] and oxygen tension [PO2]) leading to experimentally induced vaso- occlusion in the artificially perfused, innervated mesocecum microvascular preparation were determined. Microvascular obstruction was induced by decrease in Pa; the lower the Pa, the greater the peripheral resistance as well as the extent of obstruction. The cells involved in the obstruction were recovered by vasodilation (secondary to denervation) and increase in Pa. Densitometric analysis of density gradient-separated infused and trapped cells was supplemented with morphological analysis to ascertain the involvement of density classes as well as morphological types seen in oxy and deoxy sickle blood. The trapping phenomenon was sensitive to PO2. Percentage of densest gradient classes, ie, fraction 3 (F3; mainly dense unsicklable SS discocytes [USDs]) and fraction 4 (F4; irreversibly sickled cells [ISCs] and the densest discocytes), showed a significant increase in trapping when perfusion was switched from oxy to deoxy perfusate. Morphological analysis revealed that unsicklable SS discocytes are more effectively trapped when deoxygenated. The deoxygenation of infused cells did not further change the percentage of ISCs trapped, suggesting that ISCs are equally capable of sequestration in the oxy and the deoxy states. The venous effluent showed a selective and significant depletion of dense cells (F4) and ISC counts at all Pa. We conclude that the progressive obstruction of the microcirculation by sickle cells involves selective sequestration of the densest classes of cells and that this mechanism might explain their partial disappearance during painful sickle cell crisis.

scholarly journals Red cells in sickle cell crisis: observations on the pathophysiology of crisis

Blood ◽  
1977 ◽  
Vol 49 (6) ◽  
pp. 967-979 ◽  
Author(s):  
EE Rieber ◽  
G Veliz ◽  
S Pollack
Keyword(s):  
Sickle Cell ◽  
Red Cells ◽  
Red Cell ◽  
Molecular Abnormality ◽  
Sickle Cell Crisis ◽  
Sickle Cell Crises

Abstract The pathophysiology of the occurrence and resolution of sickle cell crisis is unknown. The molecular abnormality is constant, while crisis is episodic. In the present study, red cell filterability and sickling with deoxygenation have been measured during sickle cell crises. Recovery from sickle crisis is associated with an increased filterability of the circulating red cell and a decreased susceptibility of the red cell to sickle with deoxygenation (p less than 0.05). The possibility that these changes are responsible for the resolution of crisis is suggested.

scholarly journals The percentage of dense red cells does not predict incidence of sickle cell painful crisis

Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 301-303 ◽  
Author(s):  
HH Billett ◽  
K Kim ◽  
ME Fabry ◽  
RL Nagel
Keyword(s):  
Sickle Cell ◽  
Gradient Centrifugation ◽  
Red Cells ◽  
Small Subset ◽  
Sickle Cells ◽  
Alpha Thalassemia ◽  
Cellular Factors ◽  
Alpha Gene ◽  
Gene Status ◽  
Painful Crisis

Abstract To test the hypothesis that the tendency of hemoglobin S (HbS) to polymerize within cells is the major determinant of the incidence of vaso-occlusive episodes, we have examined the effect of the percentage of dense cells (as measured by Percoll-Stractan continuous density gradient centrifugation) on the frequency of painful crises in a group of 36 patients with sickle cell disease. No correlation was found between the percentage of dense cells and admissions for crisis. Among the patients with known alpha-gene status (n = 25), the strong correlation between decreased dense cells and alpha-thalassemia (- alpha/alpha alpha) reported previously was confirmed (P less than .001). In addition, in this small subset, patients with alpha- thalassemia (-alpha/alpha alpha) appeared to have a marginally increased number of admissions for sickle cell crisis (t = 2.1910, P less than .05), which was independent of the percentage of dense cells. We conclude that the percentage of dense sickle cells cannot predict the incidence of painful crisis, suggesting that other factors (microcirculatory regulation or other humoral and cellular factors) are more important in the generation maintenance of painful crises than the necessary, but not sufficient, tendency of HbS-containing red cells to sickle.

scholarly journals The percentage of dense red cells does not predict incidence of sickle cell painful crisis

Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 301-303 ◽  
Author(s):  
HH Billett ◽  
K Kim ◽  
ME Fabry ◽  
RL Nagel
Keyword(s):  
Sickle Cell ◽  
Gradient Centrifugation ◽  
Red Cells ◽  
Small Subset ◽  
Sickle Cells ◽  
Alpha Thalassemia ◽  
Cellular Factors ◽  
Alpha Gene ◽  
Gene Status ◽  
Painful Crisis

To test the hypothesis that the tendency of hemoglobin S (HbS) to polymerize within cells is the major determinant of the incidence of vaso-occlusive episodes, we have examined the effect of the percentage of dense cells (as measured by Percoll-Stractan continuous density gradient centrifugation) on the frequency of painful crises in a group of 36 patients with sickle cell disease. No correlation was found between the percentage of dense cells and admissions for crisis. Among the patients with known alpha-gene status (n = 25), the strong correlation between decreased dense cells and alpha-thalassemia (- alpha/alpha alpha) reported previously was confirmed (P less than .001). In addition, in this small subset, patients with alpha- thalassemia (-alpha/alpha alpha) appeared to have a marginally increased number of admissions for sickle cell crisis (t = 2.1910, P less than .05), which was independent of the percentage of dense cells. We conclude that the percentage of dense sickle cells cannot predict the incidence of painful crisis, suggesting that other factors (microcirculatory regulation or other humoral and cellular factors) are more important in the generation maintenance of painful crises than the necessary, but not sufficient, tendency of HbS-containing red cells to sickle.

Red cells in sickle cell crisis: observations on the pathophysiology of crisis

Blood ◽  
1977 ◽  
Vol 49 (6) ◽  
pp. 967-979
Author(s):  
EE Rieber ◽  
G Veliz ◽  
S Pollack
Keyword(s):  
Sickle Cell ◽  
Red Cells ◽  
Red Cell ◽  
Molecular Abnormality ◽  
Sickle Cell Crisis ◽  
Sickle Cell Crises

The pathophysiology of the occurrence and resolution of sickle cell crisis is unknown. The molecular abnormality is constant, while crisis is episodic. In the present study, red cell filterability and sickling with deoxygenation have been measured during sickle cell crises. Recovery from sickle crisis is associated with an increased filterability of the circulating red cell and a decreased susceptibility of the red cell to sickle with deoxygenation (p less than 0.05). The possibility that these changes are responsible for the resolution of crisis is suggested.

scholarly journals Role of Emergency Automated Red Cell Exchange in Sickle Cell Crisis: A Case Report

2020 ◽  
Vol 13 ◽  
pp. 117954762097020
Author(s):  
Anubhav Gupta ◽  
Kiran Chaudhary ◽  
Rajnish Kaushik
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anaemia ◽  
Symptomatic Improvement ◽  
Red Cells ◽  
Acute Chest Syndrome ◽  
Compound Heterozygous ◽  
Red Cell ◽  
Transfusion Therapy ◽  
Sickle Cell Crisis ◽  
Patient At Risk

For many years main stay of treatment for sickle cell anaemia was transfusion therapy. But repeated transfusions put the patient at risk of iron overload. Automated red cell exchange is an evolving and newer technique which rapidly removes the sickle cells and has benefit in decreasing sickle cell load and related complications. Red cell exchange is a therapeutic procedure in which the patient’s whole blood is processed centrifugally in cell separator. Patient’s red cells are separated from other blood components and removed and replaced with donor red cells and colloids. We report our first experience of automated red cell exchange in 24-year-old female diagnosed case of sickle cell anaemia presented to us with acute chest syndrome with septic shock. Red cell exchange was planned to tide over the acute sickle cell crisis and provide symptomatic improvement. We also highlight that compound heterozygous thalassaemia could be associated with sickle cell disease which could make the diagnosis difficult. New generation automated Apheresis equipment’s provides better monitoring of the procedure that can be useful in severely ill patients also.

scholarly journals Yoda1 and phosphatidylserine exposure in red cells from patients with sickle cell anaemia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. Wadud ◽  
A. Hannemann ◽  
D. C. Rees ◽  
J. N. Brewin ◽  
J. S. Gibson
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anaemia ◽  
Red Cells ◽  
Mechanosensitive Channel ◽  
Sickle Cells ◽  
Molecular Identity ◽  
Calphostin C ◽  
Intracellular Ca ◽  
Pkc Inhibitors ◽  
Low Levels

AbstractPhosphatidylserine (PS) exposure is increased in red cells from sickle cell anaemia (SCA) patients. Externalised PS is prothrombotic and attractive to phagocytes and activated endothelial cells and thus contributes to the anaemic and ischaemic complications of SCA. The mechanism of PS exposure remains uncertain but it can follow increased intracellular Ca2+ concentration ([Ca2+]i). Normally, [Ca2+]i is maintained at very low levels but in sickle cells, Ca2+ permeability is increased, especially following deoxygenation and sickling, mediated by a pathway sometimes called Psickle. The molecular identity of Psickle is also unclear but recent work has implicated the mechanosensitive channel, PIEZO1. We used Yoda1, an PIEZO1 agonist, to investigate its role in sickle cells. Yoda1 caused an increase in [Ca2+]i and PS exposure, which was inhibited by its antagonist Dooku1 and the PIEZO1 inhibitor GsMTx4, consistent with functional PIEZO1. However, PS exposure did not necessitate an increase in [Ca2+]i. Two PKC inhibitors were also tested, chelerytherine chloride and calphostin C. Both reduced PS exposure whilst chelerytherine chloride also reduced Yoda1-induced increases in [Ca2+]i. Findings are therefore consistent with the presence of PIEZO1 in sickle cells, able to mediate Ca2+ entry but that PKC was also involved in both Ca2+ entry and PS exposure.

scholarly journals Prolongation of sickle cell survival by dimethyl adipimidate is compromised by immune sensitization

Blood ◽  
1984 ◽  
Vol 64 (1) ◽  
pp. 161-165 ◽  
Author(s):  
MS Guis ◽  
WM Lande ◽  
N Mohandas ◽  
R Pennathur-Das ◽  
H Preisler ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Initial Study ◽  
Red Cells ◽  
Adult Males ◽  
Cell Disease ◽  
Sickle Cells

Abstract The effect of dimethyl adipimidate (DMA), an amino-reactive crosslinking reagent with demonstrated antisickling properties in vitro, on the survival of 51Cr-labeled autologous sickle cells was evaluated in five adult males with sickle cell anemia. The survival of cells pretreated with 5 mmol/L DMA (pH 7.4), normal (t1/2 28–33 days) in four subjects and near-normal (t1/2 20 days) in the fifth, was considerably longer than that usually observed in sickle cell disease. In fact, the effect of DMA on the survival of sickle cells in vivo equals or exceeds that of any other agent tested to date. In three subjects, the survival of a second infusion of DMA-treated red cells was much shorter (t1/2 1.8, 3, 4.5 days) than in the initial study. An antibody was detected in the serum of these subjects that was directed to DMA-treated red cells. Modification of the immunogenicity of treated cells will be required before further consideration of DMA for use in the therapy of sickle cell anemia.

scholarly journals The role of WNK in modulation of KCl cotransport activity in red cells from normal individuals and patients with sickle cell anaemia

2019 ◽  
Vol 471 (11-12) ◽  
pp. 1539-1549
Author(s):  
David C.-Y. Lu ◽  
Anke Hannemann ◽  
Rasiqh Wadud ◽  
David C. Rees ◽  
John N. Brewin ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Sickle Cell ◽  
Sickle Cell Anaemia ◽  
Kinase Inhibitors ◽  
Red Cells ◽  
Red Cell ◽  
Sickle Cells ◽  
Kcl Cotransport ◽  
Pre Treatment

AbstractAbnormal activity of red cell KCl cotransport (KCC) is involved in pathogenesis of sickle cell anaemia (SCA). KCC-mediated solute loss causes shrinkage, concentrates HbS, and promotes HbS polymerisation. Red cell KCC also responds to various stimuli including pH, volume, urea, and oxygen tension, and regulation involves protein phosphorylation. The main aim of this study was to investigate the role of the WNK/SPAK/OSR1 pathway in sickle cells. The pan WNK inhibitor WNK463 stimulated KCC with an EC50 of 10.9 ± 1.1 nM and 7.9 ± 1.2 nM in sickle and normal red cells, respectively. SPAK/OSR1 inhibitors had little effect. The action of WNK463 was not additive with other kinase inhibitors (staurosporine and N-ethylmaleimide). Its effects were largely abrogated by pre-treatment with the phosphatase inhibitor calyculin A. WNK463 also reduced the effects of physiological KCC stimuli (pH, volume, urea) and abolished any response of KCC to changes in oxygen tension. Finally, although protein kinases have been implicated in regulation of phosphatidylserine exposure, WNK463 had no effect. Findings indicate a predominant role for WNKs in control of KCC in sickle cells but an apparent absence of downstream involvement of SPAK/OSR1. A more complete understanding of the mechanisms will inform pathogenesis whilst manipulation of WNK activity represents a potential therapeutic approach.

scholarly journals New Observations on Sickle Cells

Blood ◽  
1954 ◽  
Vol 9 (1) ◽  
pp. 39-45 ◽  
Author(s):  
M. BESSIS ◽  
M. BRICKA ◽  
J. BRETON-GORIUS ◽  
J. TABUIS
Keyword(s):  
Electron Microscope ◽  
Sickle Cell ◽  
Special Form ◽  
Phase Contrast ◽  
Red Cells ◽  
Red Cell ◽  
Surface Layers ◽  
Characteristic Appearance ◽  
Sickle Cells

Abstract Observations made on sickle cells with phase contrast and with the electron microscope lead to the following conclusions. 1. When the red cell sickles, its oscillatory movements cease. 2. Spherical red cells give rise to a special form of sickle cell. 3. Myelin forms, whether attached to the cell or free, become rigid when the tension of oxygen is reduced. 4. The electron microscope, combined with the technic of moulage, shows that the sickle cell contains striated rod-like structures, which give a characteristic appearance to the surface of the sickle cell. 5. Agglutination by appropriate antisera does not occur to any extent in sickled cells, because these rigid structures do not form myelin forms. This is additional evidence of the importance of the formation of viscous surface layers already described as part of the mechanism of agglutination.

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