Studying the reversible aggregation of red blood cells (RBC), which is one of the main factors determining the blood microcirculation is of importance for modern cardiology because the widespread application of different antiplatelet agents and anticoagulants in clinical practice may affect the blood rheology also via the alteration of RBC aggregation. Administration of the antiplatelet and anticoagulants agents into blood is based on general assumptions about the average doses of the drug, which often do not fully comply with the requirements of the personalized medicine. In this work, we compare the blood aggregation properties measured by laser aggegometry techniques in-vitro in blood samples with the properties of blood rheology measured with digital capillaroscopy in-vivo in the nail beds capillaries of patients suffering from the coronary heart disease (CHD). We demonstrate the impairment of these properties and high correlation of their alterations for patients suffering from the CHD with different stages of rheology disorders. Good agreement between the results obtained with the used diagnostic techniques, laser aggregometry, laser tweezers and digital capillaroscopy, and their applicability for the diagnostics of abnormalities of rheological properties of blood are demonstrated.
Different optical techniques are widely used for the characterization of red blood cells (RBC) aggregation. Advantages of these techniques are in their relative simplicity and possibility to analyze a large number or single cells simultaneously without mechanical contact with investigated red blood cells. RBC aggregability refers to the cells' ability to form multicellular aggregates in the presence of different plasma proteins or macromolecules. Opposing forces determine the extent of aggregation by: the repulsive force between the negatively charged cells, the cell-cell adhesion induced by the macromolecules, and the disaggregating flow-induced shear stress. Kinetic and dynamic features of the cells interaction can characterize the RBC aggregation process. In our previous publication, we used de Gennes’ approach that describes macromolecules behavior in the space between two solid surfaces for analysis of the kinetics of rouleaux formation. The present study was undertaken to examine the RBC aggregation in dextran 150 kDa solution, in the light of de Gennes’ model, in a concentrated RBC suspension using the diffuse light scattering technique as well on the single cell level in a highly diluted suspension with pairs of the cells using the optical tweezers. We demonstrated that the kinetics (timing process) and the mechanical features (forces balance characterization) of dextran 150-induced RBC aggregation are not identical according to their contribution to the aggregation process. Optical methods provided handy tools to study the kinetic and dynamic peculiarities of RBCs aggregation and disaggregation, which can be extremely useful for controlling the blood microcirculation especially in cases of hemorheological disorders.
Microrheological parameters of red blood cells (RBCs) and blood viscosity were studied by different optical and rheometric techniques. Measurements were performed under in vitro condition both on the EDTA-stabilized whole blood samples at various temperatures and on the RBCs in autologous serum without platelets at different concentrations of proaggregant macromolecules (Dextran 150, Dextran 500 and albumin). The nonlinear dependences of the aggregation parameters on the concentration of the proaggregant macromolecules in autologous serum were observed. Rheometry of human whole blood samples demonstrates a power law dependence of the suspension viscosity on temperature at such shear rates that allow the RBC aggregation. We assume that there may be an unaccounted temperature dependent synergetic effect of plasma proteins/macromolecules on RBC aggregation and interaction and, consequently, on the blood viscosity.
Yu-Chung Lin, Lin-Wei Tsai, Elena Perevedentseva, Jani Mona, Chia-Liang Cheng, Hsin-Hou Chang, Ching-Hui Lin, Der-Shan Sun, Andrei Lugovtsov, Alexander Priezzhev
Nanodiamond has been proven to be biocompatible and proposed for various biomedical applications. Recently, nanometer-sized diamonds have been demonstrated as an effective Raman/fluorescence probe for bio-labeling, as well as, for drug delivery. Bio-labeling/drug delivery can be extended to the human blood system, provided one understands the interaction between nanodiamonds and the blood system. Here, the interaction of nanodiamonds (5 and 100 nm) with human red blood cells (RBC) in vitro is discussed. Measurements have been facilitated using Raman spectroscopy, laser scanning fluorescence spectroscopy, and laser diffractometry (ektacytometry). Data on cell viability and hemolytic analysis are also presented. Results indicate that the nanodiamonds in the studied condition do not cause hemolysis, and the cell viability is not affected. Importantly, the oxygenation/deoxygenation process was not found to be altered when nanodiamonds interacted with the RBC. However, the nanodiamond can affect some RBC properties such as deformability and aggregation in a concentration dependent manner. These results suggest that the nanodiamond can be used as an effective bio-labeling and drug delivery tool in ambient conditions, without complicating the blood's physiological conditions. However, controlling the blood properties including deformability of RBCs and rheological properties of blood is necessary during treatment.
The main goal of this work is to develop a fast tool for calculation of light scattered by single large optically soft spheroidal particles. In particular, such particles mimic biological cells (e.g., red blood cells (RBC)). Methodology of calculation of light scattering by arbitrarily oriented optically soft spheroidal particles in Ray-Wave Approximation (RWA) is presented. We show that RWA permits to quickly and accurately calculate the angular distributions of the intensities of light scattered from particles mimicking RBC.
In this work, the analysis of human and rat red blood cells (RBC) deformability, internal viscosity and yield
stress of RBC in norm and ischemia was performed by means of laser diffractometry - a modern technique allowing for
measuring the flexibility of RBC, which determines the blood flow parameters in vessels. Ischemic diseases of people
and animals are accompanied with deterioration of microrheologic properties of their blood, in particular, with
impairing the RBC deformability. Human RBCs were obtained from the blood of healthy individuals and from patients
suffering from ischemic diseases. The RBC deformability indices from both groups of individuals were measured. Rat
RBCs were obtained from a control group of animals and from a group with experimentally induced ischemia (EII).
This animal model is frequently used for studying the response of an organism to ischemia. The effect of semax, a
medication that is frequently used for therapeutic treatments of human brain diseases in clinical practice, on RBC
deformability was studied with its application in vitro and in vivo. It is shown that in human ischemic patients, the
deformability index of RBC was lower than that from healthy individuals. Both in vivo and in vitro applied semax positively influences the impaired deformability properties of RBCs of ischemic rats.
The main goal of this work is the fast analysis of light scattered by a large optically soft spheroidal particle (size
parameter ka > 20). In particular, these particles mimic single cells (e.g., red blood cells (RBC)) and their
aggregates. Methodology of calculation of light scattering by arbitrarily oriented optically soft spheroidal particles
in geometric optics approximation is presented. We show that the geometric optics approximation permits to
quickly calculate the angular distributions of the intensities and phases of light scattered from optically soft
particles, such as erythrocytes.
Ischemic diseases of people and animals are accompanied with deterioration of microrheologic properties of their
blood, in particular, with impairing red blood cells (RBC) deformability. In this work, the analysis of human and rat
RBC deformability in norm and ischemia was performed by means of the laser diffractometry - a modern technique
allowing for measuring the flexibility of RBC, which determines the blood flow parameters in vessels. Human RBC
were obtained from the blood of healthy individuals and from patients suffering from ischemic diseases. Human RBC
deformability from both groups of individuals was measured. Rat RBC were obtained from a control group of animals
and from a group with experimentally induced ischemia (EII). This animal model is frequently used for studying the
response of an organism to ischemia. The effect of Semax, a medication that is frequently used for therapeutic
treatments of human brain diseases in clinical practice, on RBC deformability was studied with its application in vitro
and in vivo.
It is shown that in human ischemic patients, the deformability of RBC was lower than that from healthy individuals.
Both in vivo and in vitro applied semax positively influences the impaired deformability properties of RBC of ischemic rats.
Reduced ability of erythrocytes of ischemic rats to change their shape in shear flow and semax effect on the
deformability of erythrocytes are studied with laser diffractometry technique. It is shown that both in vivo and in vitro
applied semax positively influences the impaired deformability properties of erythrocytes of ischemic rats.
Reduced ability of erythrocytes of hemorrhagic rats to change their shape under hydrodynamic stress in shear flow in vitro is explored with a laser diffractometry technique. It is shown that 1.5 hours after a stressful sonic influence on rats, the ability of their erythrocytes to deform, quantitatively characterized by the deformability index, decreases reaching the value of 11 ± 2% below the initial value measured before the sonic influence.
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