ИСТИНА

Methods based on the use of diffuse elastic light scattering and diffractometry are widely used to measure several parameters that characterize the microrheological properties of blood [1]. The state of human organism essentially depends on the microrheological properties of red blood cells (RBC) and platelets aggregation as well as RBC deformability. The importance of monitoring these properties is determined by the need to correct them with the use of various drugs or with the help of drug plasmapheresis procedures. The procedure of therapeutic plasmapheresis is a method of extracorporeal hemocorrection aimed at changing the qualitative and quantitative composition, correcting the physicochemical state of the blood, removing pathogenic substances from the circulating bloodstream, normalizing the immune response. So far there is no information about the effect of plasmapheresis on blood microrheological properties. The paper demonstrates the physical foundations of the used laser-optical methods and their application for estimating the effect of the plasmapheresis procedure on the blood microrheology and microcirculation. All measurements of deformability and aggregation of RBC were performed using the commercially available Rheoscan system (Rheomeditech, Korea). The essence of laser diffractometry is in obtaining and subsequent analysis of the obtained diffraction pattern from a highly diluted suspension of RBCs at rest and shear flow. Analysing the obtained diffraction patterns one can calculate the deformability index dependence on shear stress that characterise the ability of RBC to elastically deform in the flow. The light scattering (laser aggregometry) technique allows for assessing the parameters characterizing the ability of the RBCs to reversibly aggregate in large ensembles of the cells. 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 RBC for obtaining the characteristic time of aggregates formation (aggregation rate), aggregation index as well as hydrodynamic strength of aggregates. Platelet aggregation parameters were assessed using the laser aggregometer of platelets “Biola” (BIOLA LLC., Russia) implementing the turbidimetry technique. Light transmission kinetics and optical density fluctuation during the platelet aggregation process induced by adenosine diphosphate (ADP) was registered in platelet-rich plasma with subsequent calculations of the aggregation index and rate as well as the aggregate size. All these techniques are convenient, fast and relatively simple for in vitro measuring with EDTA- or sodium citrate-stabilized human blood samples drawn from patients before and after the procedure of plasmapheresis. The results of in vitro measurements in blood of a group comprising 10 pregnant women, the indices of RBC deformability, aggregation of RBCs and platelets, hydrodynamic strength, characteristic time of RBC aggregates formation before and after the procedure of plasmapheresis are presented. A significant increase in platelet aggregation, a decrease in RBC aggregation, and a slight decrease in the deformability of RBCs were found. This work was supported by the grant of Interdisciplinary Scientific and Educational School of Lomonosov Moscow State University «Photonic and Quantum technologies. Digital medicine» (grant No. 23-Ш06-03).