Ektacytometric Analysis of Factors Regulating Red Cell Deformability

Mohandas, Narla; Clark, Margaret; Jacobs, Mark S.; Groner, W.; Shohet, Stephen B.

doi:10.1007/978-3-642-67756-4_14

Cited by 13 publications

(22 citation statements)

References 5 publications

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“…In rare cases such as elliptocytosis, cells behave differently in simple shear flow and only collectively orient in the direction of the streamlines at a high shear stress (35). This behavior markedly affects the RBC-DD and wrongly indicates the presence of a large fraction of nondeformable cells.…”

Section: Discussionmentioning

confidence: 99%

Measurement of the distribution of red blood cell deformability using an automated rheoscope

et al. 2002

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Section: Discussionmentioning

confidence: 99%

Measurement of the distribution of red blood cell deformability using an automated rheoscope

et al. 2002

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“…Whole cell deformability was measured by a laser diffraction method employing the ektacytometer (15) with the new image analysis system as described (14). In this instrument, deformation of the laser diffraction pattern of suspended cells provides a measure of cell deformation.…”

Section: Methodsmentioning

confidence: 99%

“…that the DI and the ellipticity respond identically to applied shear stress, and thus the DI curve provides an accurate measure of cell deformation (14). From the DI curve, two pieces of information that characterize cell deformability can be obtained.…”

Section: Methodsmentioning

confidence: 99%

“…First, the DImax represents the cell defromation at maximum shear stress, and varies with suspending medium osmolality. Measurement of DImax under varying osmotic conditions permits the identification of erythrocyte surface area/volume ratio and increased internal viscosity as factors responsible for reduced whole cell deformability (14). Second, the initial slope of the DI curve, which contains all the information about membrane resistance to cell deformation, was shown to permit identification of increased membrane shear modulus in those cases where a normal DImax could be obtained (14).…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we have shown that measurement ofwhole cell deformability with the ektacytometer at various osmotic strengths can be used to distinguish the separate contributions of internal viscosity, surface area/volume ratio, and membrane shear modulus to the behavior of abnormally deformable cells (14). We have used these methods to study cells during prolonged and acute depletion and after rapid Ca loading using the ionophore A23187.…”

Section: Introductionmentioning

confidence: 99%

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Separate Mechanisms of Deformability Loss in ATP-depleted and Ca-loaded Erythrocytes

Clark¹,

Mohandas²,

Féo³

et al. 1981

J. Clin. Invest.

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A B S T R A C T Membrane rigidity has been widely accepted as the dominant cause of reduced deformability both of ATP-depleted erythrocytes and erythrocytes containing excess calcium (Ca). However, recent studies have shown normal membrane deformability in ATP-depleted erythrocytes. In addition, Ca accumulation causes massive ion and water loss, and it has been shown that extensive dehydration causes an increase in intracellular viscosity with attendant loss of whole cell deformability. To obtain a detailed understanding of the processes accompanying ATP depletion and/or Ca accumulation that limit cell deformability, we have used a viscodiffractometric method to identify the cellular factors contributing to reduced whole cell deformability.Analysis of the influence of the suspending medium osmolality on deformability showed the presence of two independent processes. One was a Ca-independent reduction in cell surface area/volume ratio, resulting from the spheroechinocyte formation that follows total ATP consumption. The other was a Cadependent increase in intracellular viscosity resulting from a Ca-induced loss of intracellular potassium and water. This deformability loss due to increased intracellular viscosity was found for cells depleted of ATP in the presence of Ca and in cells treated with Ca and A23187 without prior depletion. lonophoretreated cells at high Ca concentration (>500 ,uM) formed spheroechinocytes with reduced surface area and a further loss of whole cell deformability. The rate of deformability loss associated with Ca-induced spheroechinocytosis was much more rapid than that A portion of this material has been published in abstract form in 1979. Blood. 54(Suppl. 1): 25a. This is publication number 21 from the MacMillan-Cargill Hematology Research Laboratory.Address reprint requests to Dr. Clark in California.

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A biomimetic microfluidic chip to study the circulation and mechanical retention of red blood cells in the spleen

et al. 2015

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Red blood cells (RBCs) are deformable and flow through vessels narrower than their own size. Their deformability is most stringently challenged when they cross micrometer-wide slits in the spleen. In several inherited or acquired RBC disorders, blockade of small vessels by stiff RBCs can trigger organ damage, but a functional spleen is expected to clear these abnormal RBCs from the circulation before they induce such complications. We analyzed flow behavior of RBCs in a microfluidic chip that replicates the mechanical constraints imposed on RBCs as they cross the human spleen. Polymer microchannels obtained by soft lithography with a hydraulic diameter of 25 lm drove flow into mechanical filtering units where RBCs flew either slowly through 5-to 2-lm-wide slits or rapidly along 10-lm-wide channels, these parallel paths mimicking the splenic microcirculation. Stiff heated RBCs accumulated in narrow slits seven times more frequently than normal RBCs infused simultaneously. Stage-dependent retention of Plasmodium falciparuminfected RBCs was also observed in these slits. We also analyzed RBCs from patients with hereditary spherocytosis and observed retention for those having the most altered mechanical properties as determined by ektacytometry. Thus, in keeping with previous observations in vivo and ex vivo, the chip successfully discriminated poorly deformable RBCs based on their distinct mechanical properties and on the intensity of the cell alteration. Applications to the exploration of the pathogenesis of malaria, hereditary spherocytosis, sickle cell disease and other RBC disorders are envisioned.

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Ektacytometric Analysis of Factors Regulating Red Cell Deformability

Cited by 13 publications

References 5 publications

Measurement of the distribution of red blood cell deformability using an automated rheoscope

Measurement of the distribution of red blood cell deformability using an automated rheoscope

Separate Mechanisms of Deformability Loss in ATP-depleted and Ca-loaded Erythrocytes

A biomimetic microfluidic chip to study the circulation and mechanical retention of red blood cells in the spleen

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