Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®...Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®erent endogenous and exogenous factors.One such factor is nitric oxide(NO),which is mainly produced by endothelial cells(EC)from L-arginine amino acid in the circulatory system.Since the mechanisms of the RBC-endothelium interplay are not clear up to date and considering its possible clinical importance,the aims of this study are to investigate in vitro:(1)The effect of L-arginine induced NO on RBC aggregation and adhesion to endothelium;(2)the NO e®ect on RBC aggregation and deformation induced by L-arginine and sodium nitroprusside without the presence of endothelium in the samples.The RBC aggregation and adhesion to a monolayer of EC were studied using optical tweezers(OT).The RBC deformability and aggregation without endothelium in the samples were studied using the flow chamber method and Myrenne aggregometer.We confirmed that NO increases deformability and decreases aggregation of RBCs.We showed that the soluble guanylate cyclase pathway appears to be the only NO signaling pathway involved.In the samples with the endothelium,the "bell-shaped"dependence of RBC aggregation force on L-arginine concentration was observed,which improves our knowledge about the process of NO production by endothelium.Additionally,data related to L-arginine accumulation by endothelium were obtained:Necessity of the presence of extracellular L-arginine stated by other authors was put under question.In our study,NO decreased the RBC-endothelium adhesion,however,the tendency appeared to be weak and was not confirmed in another set of experiments.To our knowledge,this is the first attempt to measure the forces of RBC adhesion to endothelium monolayer with OT.展开更多
Laser elktacytometry is a technique widely used for measuring the deformability of red blood cells(erythrocytes)in blood samples in vitro.In ektacytometer,a flow of highly diluted suspension of erythrocytes in variabl...Laser elktacytometry is a technique widely used for measuring the deformability of red blood cells(erythrocytes)in blood samples in vitro.In ektacytometer,a flow of highly diluted suspension of erythrocytes in variable shear stress conditions is iluninated with a laser beam to obtain a diffraction pattern.The diffraction pattern provides information about the shapes(shear induced elongations)of the cells under investigation.This paper is dedicated to developing the technique of laser ektacytometry s0 that it would enable one to measure the distrilbution of the erythrocytes in deformability.We discuss the problem of calibration of laser elktacytometer and test a novel data processing algorithm allowing to determine the parameters of the distribution of ery-throcytes deformability.Experimentally,we examined 12 specimens of blood of rats under the action of 4 shear stresses.Analysis of the data shows that in conditions of a limited range of digitizing the diffraction patterns,the measurement errors for the mean deformability,deform-ability scatter and the skewness of erythrocytes distribution in deformability by our method are respectively 15%,20%and 20%.展开更多
基金supported by the Russian Science Foundation Grant No.22-15-00120.
文摘Red blood cells(RBCs)are the most abundant human blood cells.RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation.In turn,RBC properties depend on di®erent endogenous and exogenous factors.One such factor is nitric oxide(NO),which is mainly produced by endothelial cells(EC)from L-arginine amino acid in the circulatory system.Since the mechanisms of the RBC-endothelium interplay are not clear up to date and considering its possible clinical importance,the aims of this study are to investigate in vitro:(1)The effect of L-arginine induced NO on RBC aggregation and adhesion to endothelium;(2)the NO e®ect on RBC aggregation and deformation induced by L-arginine and sodium nitroprusside without the presence of endothelium in the samples.The RBC aggregation and adhesion to a monolayer of EC were studied using optical tweezers(OT).The RBC deformability and aggregation without endothelium in the samples were studied using the flow chamber method and Myrenne aggregometer.We confirmed that NO increases deformability and decreases aggregation of RBCs.We showed that the soluble guanylate cyclase pathway appears to be the only NO signaling pathway involved.In the samples with the endothelium,the "bell-shaped"dependence of RBC aggregation force on L-arginine concentration was observed,which improves our knowledge about the process of NO production by endothelium.Additionally,data related to L-arginine accumulation by endothelium were obtained:Necessity of the presence of extracellular L-arginine stated by other authors was put under question.In our study,NO decreased the RBC-endothelium adhesion,however,the tendency appeared to be weak and was not confirmed in another set of experiments.To our knowledge,this is the first attempt to measure the forces of RBC adhesion to endothelium monolayer with OT.
基金supported by RFBR grants No.13-02-01372 and No.12-02-01329.
文摘Laser elktacytometry is a technique widely used for measuring the deformability of red blood cells(erythrocytes)in blood samples in vitro.In ektacytometer,a flow of highly diluted suspension of erythrocytes in variable shear stress conditions is iluninated with a laser beam to obtain a diffraction pattern.The diffraction pattern provides information about the shapes(shear induced elongations)of the cells under investigation.This paper is dedicated to developing the technique of laser ektacytometry s0 that it would enable one to measure the distrilbution of the erythrocytes in deformability.We discuss the problem of calibration of laser elktacytometer and test a novel data processing algorithm allowing to determine the parameters of the distribution of ery-throcytes deformability.Experimentally,we examined 12 specimens of blood of rats under the action of 4 shear stresses.Analysis of the data shows that in conditions of a limited range of digitizing the diffraction patterns,the measurement errors for the mean deformability,deform-ability scatter and the skewness of erythrocytes distribution in deformability by our method are respectively 15%,20%and 20%.
