CC BY
14B-I-18
Laser measurements of erythrocyte aggregation in patients suffering from arterial hypertension
A. Lugovtsov1, L. Dyachuk2, P. Ermolinskiy3, A. Maslyanitsina3, A. Priezzhev1 1M. V. Lomonosov Moscow State University,
Department of Physics and International Laser Center, Moscow, Russian Federation
2M. V. Lomonosov Moscow State University, Medical Research and Education Center, Moscow,
Russian Federation
3M. V. Lomonosov Moscow State University, Department of Physics, Moscow, Russian Federation
Erythrocyte reversible aggregation is one the major phenomena that affect blood microcirculation. Alterations in aggregation properties lead to changing the blood viscosity and, as a consequence, to changes in blood flow through vessels and capillaries. This can lead to significant impairment of blood function, which increases a risk of occurrence of vascular concomitant diseases, and even the mortality especially in the case of cardiovascular pathologies. The erythrocytes aggregation and interaction properties are expected to be impaired in patients with arterial hypertension (AH). Thus, it is necessary to control these parameters during diagnostics and treatment of cardiovascular diseases. In this work, complex studies of the alterations of aggregation parameters of erythrocytes in whole blood samples and of pair interaction of single cells in patients suffering from such a socially significant disease as AH were conducted by laser methods.
The light scattering (laser aggregometry) technique allows for assessing the parameters characterizing the ability of the erythrocytes to reversibly aggregate in large ensembles of the cells. All measurements were performed using the commercially available Rheoscan system (Rheomeditech, Korea). This technique is convenient, fast and relatively simple for in vitro measuring the aggregation properties of erythrocytes. It allows to register the kinetics of the spontaneous aggregation (time dependence of light intensity forward scattered from a sample of whole blood at rest) and shear-induced disaggregation (shear stress dependence of light intensity backscattered from a sample of whole blood under shear flow) of erythrocytes for obtaining the characteristic time of aggregates formation (aggregation rate), aggregation index as well as hydrodynamic strength of aggregates [1].
Home-made double channeled optical tweezers (OT) were used for measuring the aggregation velocity as well as the interaction forces on cellular level [2]. OT are formed by two single-mode Nd:YAG lasers and a water-immersion objective with high numerical aperture. OT allow for freely manipulating the individual cells with a tightly focused laser beam without direct mechanical contact.
In vitro measurements were performed with EDTA-stabilized human blood samples drawn from patients with AH (88 people) and practically healthy volunteers - control (18 people). It was shown that in AH-patients, the aggregation speed of the erythrocytes and forces of the cells interaction are significantly increased relative to those in the control group while the ability of erythrocytes to aggregate in large ensembles is significantly enhanced relative to that in the control group. Basing on the obtained results one can conclude that laser aggregometry and optical trapping and manipulation are appropriate techniques for estimating the blood aggregation properties in whole blood samples and on the level of individual cells.
The work was financially supported by the Russian Foundation for Basic Research grant No. 17-02-01200.
References
[1] A.V. Priezzhev, N.N. Firsov, J. Lademann, Light backscattering diagnostics of RBC aggregation in whole blood samples, Chapter 11 in Handbook of Optical Biomedical Diagnostics, Editor V. Tuchin, Washington: SPIE Press, pp. 651 - 674 (2012).
[2] K. Lee, M. Kinnunen, M.D.Khokhlova, E.V.Lyubin, A.V.Priezzhev, I. Meglinski, A. Fedyanin, Optical tweezers study of red blood cell aggregation and disaggregation in plasma and protein solutions, Journal of Biomedical Optics, vol. 21(3), pp. 035001 (2016).
