Comparison of three commercially available ektacytometers with different shearing geometries

Başkurt, Oğuz K.; Hardeman, Max R.; Üyüklü, Mehmet; Ülker, Pınar; Cengiz, Melike; Németh, Norbert; Shin, Sehyun; Alexy, Tamás; Meiselman, Herbert J.

doi:10.3233/bir-2009-0536

Cited by 80 publications

(59 citation statements)

References 11 publications

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“…[48, 71] Controlled exposure to glutaraldehyde and / or diamide is widely used in the literature to mimic the pathophysiological impairment of RBC mechanical properties occurring naturally, particularly in validation and sensitivity studies of new RBC deformability measurement techniques. [36, 42, 43, 45, 48, 53, 71] A high sensitivity of a technique for measuring RBC deformability to either of these chemical treatments, however, may not necessarily mean a similarly high sensitivity to the other treatment ( Fig. 3A-B ).…”

Section: Discussionmentioning

confidence: 99%

“…[22] The two techniques most frequently utilized in the vast majority of research performed to date in this area (and perhaps most accessible in the clinical settings) are the micro-pore filtration assay[23-30] and ektacytometry. [31-43] In this paper, we directly compare the measurements of RBC deformability performed using these two methodologies with the ability of RBCs to perfuse an artificial microvascular network (AMVN), a microfluidic device developed in our laboratory for modeling the dynamics of blood flow and traffic of circulating cells in the microvasculature. [44-47] We completed the comparison using RBC samples with cell deformability artificially impaired via graded exposure to glutaraldehyde (a non-specific protein cross-linker) and to diamide (a spectrin-specific cross-linker), both of which are frequently used to determine the sensitivity of various deformability metrics.…”

Section: Introductionmentioning

confidence: 99%

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The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network

Sosa

Nielsen

Vignes

et al. 2014

Clinical Hemorheology and Microcirculation

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The ability of red blood cells (RBC) to undergo a wide range of deformations while traversing the microvasculature is crucial for adequate perfusion. Interpretation of RBC deformability measurements performed in vitro in the context of microvascular perfusion has been notoriously difficult. This study compares the measurements of RBC deformability performed using micropore filtration and ektacytometry with the RBC ability to perfuse an artificial microvascular network (AMVN). Human RBCs were collected from healthy consenting volunteers, leukoreduced, washed and exposed to graded concentrations (0% – 0.08%) of glutaraldehyde (a non-specific protein cross-linker) and diamide (a spectrin-specific protein cross-linker) to impair the deformability of RBCs. Samples comprising cells with two different levels of deformability were created by adding non-deformable RBCs (hardened by exposure to 0.08% glutaraldehyde) to the sample of normal healthy RBCs. Ektacytometry indicated a nearly linear decline in RBC deformability with increasing glutaraldehyde concentration. Micropore filtration showed a significant reduction only for concentrations of glutaraldehyde higher than 0.04%. Neither micropore filtration nor ektacytometry measurements could accurately predict the AMVN perfusion. Treatment with diamide reduced RBC deformability as indicated by ektacytometry, but had no significant effect on either micropore filtration or the AMVN perfusion. Both micropore filtration and ektacytometry showed a linear decline in effective RBC deformability with increasing fraction of non-deformable RBCs in the sample. The corresponding decline in the AMVN perfusion plateaued above 50%, reflecting the innate ability of blood flow in the microvasculature to bypass occluded capillaries. Our results suggest that in vitro measurements of RBC deformability performed using either micropore filtration or ektacytometry may not represent the ability of same RBCs to perfuse microvascular networks. Further development of biomimetic tools for measuring RBC deformability (e.g. the AMVN) could enable a more functionally relevant testing of RBC mechanical properties.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network

Sosa

Nielsen

Vignes

et al. 2014

Clinical Hemorheology and Microcirculation

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“…Erythrocyte deformability was assessed using a laser diffraction Ektacytometer with a thin micro-channel as the shearing geometry (RheoScan-D300; RheoMeditech) [10,11]. The erythrocyte suspension (6 μ l) of each genotype was mixed with the PBS-PVP (polyvinylpyrrolidone) aliquot (600 μ l volume).…”

Section: Methodsmentioning

confidence: 99%

Calpain-1 knockout reveals broad effects on erythrocyte deformability and physiology

Wieschhaus

Khan

Zaidi

et al. 2012

Biochemical Journal

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Pharmacological inhibitors of cysteine proteases have provided useful insights into the regulation of calpain activity in erythrocytes. However, the precise biological function of calpain activity in erythrocytes remains poorly understood. Erythrocytes express calpain-1, an isoform regulated by calpastatin, the endogenous inhibitor of calpains. In the present study, we investigated the function of calpain-1 in mature erythrocytes using our calpain-1-null [KO (knockout)] mouse model. The calpain-1 gene deletion results in improved erythrocyte deformability without any measurable effect on erythrocyte lifespan in vivo. The calcium-induced sphero-echinocyte shape transition is compromised in the KO erythrocytes. Erythrocyte membrane proteins ankyrin, band 3, protein 4.1R, adducin and dematin are degraded in the calcium-loaded normal erythrocytes but not in the KO erythrocytes. In contrast, the integrity of spectrin and its state of phosphorylation are not affected in the calcium-loaded erythrocytes of either genotype. To assess the functional consequences of attenuated cytoskeletal remodelling in the KO erythrocytes, the activity of major membrane transporters was measured. The activity of the K+–Cl− co-transporter and the Gardos channel was significantly reduced in the KO erythrocytes. Similarly, the basal activity of the calcium pump was reduced in the absence of calmodulin in the KO erythrocyte membrane. Interestingly, the calmodulin-stimulated calcium pump activity was significantly elevated in the KO erythrocytes, implying a wider range of pump regulation by calcium and calmodulin. Taken together, and with the atomic force microscopy of the skeletal network, the results of the present study provide the first evidence for the physiological function of calpain-1 in erythrocytes with therapeutic implications for calcium imbalance pathologies such as sickle cell disease.

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“…We here analyzed the RBC aggregation in vitro under static conditions using the EAAT test according to Rotstein et al, 29 which may differ from other tests, for example, under dynamic conditions. 66,67 Furthermore, it is unclear, whether the in vitro determined RBC aggregation reflects the in vivo situation. However, in the present study we were unable to analyze the effects of RBC aggregation in coronary aspirate from RCA and SVG-RCAs on microvascular obstruction, as-by definition-we removed the aggregated coronary aspirate.…”

Section: Study Limitationsmentioning

confidence: 99%

Influence of stent implantation on erythrocyte aggregation in human native coronary arteries and saphenous vein grafts

Baars

Preibsch³

et al. 2016

Microcirculation

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Comparison of three commercially available ektacytometers with different shearing geometries

Cited by 80 publications

References 11 publications

The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network

The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network

Calpain-1 knockout reveals broad effects on erythrocyte deformability and physiology

Influence of stent implantation on erythrocyte aggregation in human native coronary arteries and saphenous vein grafts

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