ИСТИНА

The state of human organism largely depends on blood microcirculation that depends on the microrheology of red blood cells (RBCs) and on their intrinsic properties of deformability and aggregation, in particular. Cardiovascular and metabolic diseases such as arterial hypertension (AH) and diabetes mellitus (DM) can lead to impairment of blood microrheology and, consequently, microcirculation. We evaluate the feasibility of laser and optical techniques to assess microrheological effects of various molecular mechanisms affecting RBC aggregation and deformability. In particular, we show that laser tweezers and diffuse light scattering allow for assessing the changes in erythrocyte aggregation in whole blood samples and cell suspensions both on the level of single cells and on the level of large ensembles of cells. Application of these methods in vitro enable one to study the mechanisms of erythrocyte aggregation because they are sensitive to changes in the medium surrounding the cells (i.e., blood plasma, serum or model solutions of blood plasma proteins) and to changes in the cellular properties of the erythrocytes. Using the laser diffractometry technique we can assess the distribution of the erythrocytes in sizes and deformabilities. Using digital capillaroscopy we can monitor in vivo the alterations of blood flow parameters on the microcirculatory level where the major exchange of gases between blood and tissues takes place. The main goal of this work was to determine and interrelate the deformability and aggregation properties, forces of pair aggregation of RBCs in the samples of blood drawn from patients suffering from AH and DM, and those from healthy donors. Statistical analysis of the measurement results constituting our data base shows that in AH and DM patients, the ability of RBCs to deform is slightly reduced while the aggregation speed and forces of the cells interaction are significantly increased relative to the control group. The blood microcirculation in nailfold capillaries is impaired as well. The alterations of the parameters measured in vivo and in vitro for patients suffering from these diseases are interrelated. Good agreement between the results obtained with different techniques, and their applicability for the diagnostics of abnormalities of rheological properties of blood were demonstrated.