ИСТИНА

Nowadays the number of people suffering from diabetes mellitus (DM) increases rapidly mainly due to unhealthy nutrition and lifestyle. This disease can lead to severe alterations of vitally important systems of the human organism including the cardiovascular system and results in a damage to blood vessels and capillaries, impairment of blood hemorheology and microcirculation. Enhanced aggregation of red blood cells (RBC) and platelets is one of key factors, which determines the blood flow alteration and thereby affects the blood rheology. The ability of RBC to deform in shear flow conditions is the second major property that affects the blood microcirculation. Alterations in these properties lead to changing the blood viscosity and, consequently, to changes in capillary blood flow. This can lead to significant impairment of blood function, which increases a risk of occurrence of vascular concomitant diseases, and even the mortality. The main goal of this work is to interrelate and assess the deformability (dependance of RBC elongation on shear stress) and aggregation properties of RBC (hydrodynamic strength of RBC aggregates, characteristic time of RBC aggregates formation, aggregation index, forces of pair aggregation of RBCs and aggregation rate), platelets aggregation rate and degree in the blood samples drawn from patients suffering from DM and from healthy donors. The measurements were performed in vitro using the techniques of diffuse light scattering, turbidimetry, laser diffractometry, laser trapping and manipulation. Digital capillaroscopy was used in vivo to visualize the capillaries and quantitatively evaluate the capillary blood flow in the nailfold vessels. It was shown that in DM patients, the ability of RBC to deform is slightly reduced while the aggregation rate and forces of the cells interaction are significantly increased relative to those in the control group. The degree and rate of platelets aggregation in patients suffering from DM are increased compared with people without DM. The activation of platelets occurs more intensively and rapidly in case of DM. The blood microcirculation in nailfold capillaries is impaired as well. We have shown that the alterations of the parameters measured in vivo and in vitro for patients with different stages of 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. The study was supported by the Russian Science Foundation Grant No. 22-15-00120.