ИСТИНА

AIM: Red blood cells (RBC) aggregation is an intrinsic feature of blood that has a strong impact on its microcirculation. For a number of years it has been attracting a great attention in basic research and clinical studies. Here,we study a relationship between the RBC aggregation parameters measured at the individual cell level and in whole blood samples. METHODS: Home-made optical tweezers were used to measure the aggregating and disaggregating forces between the individual interacting RBCs in doublets, in order to evaluate the corresponding shear stresses (τ). The RheoScan aggregometer was used for the measurements of critical shear stress (CSS) in whole blood samples. RESULTS: The correlation between CSS and SASS (Single cell aggregating shear stress, i.e., τ required to stop an RBC pair from aggregating) was found. SDSS (Single cell disaggregating shear stress, i.e., τ required to disaggregate a pair of RBCs) appeared to be few times higher than CSS and SASS. CONCLUSIONS: We conclude that (1) SASS can be quantitatively compared with CSS and (2) SASS is significantly lower than SDSS. Therefore CSS should refer only to the shear stress preventing the RBCs aggregation but not to the disaggregating shear stress. The parameters characterizing the disaggregation process might serve as additional sensitive parameters to monitor the state of blood microcirculation.