Relationship between red blood cell aggregation and dextran molecular mass

Abstract

The aim of this study was to investigate the aggregation of red blood cells (RBCs) suspended in dextran solution at various levels of molecular mass. Dextran solutions at molecular mass 40, 70, 100 and 500 kDa at concentration from 2 to 5 g/dL were used to suspend the RBCs. The radius and velocity of sedimenting RBC aggregates were investigated using image analysis. The radius and sedimentation velocity of aggregates increased initially, then decreased after achieving maxima. The maximal velocity of RBC aggregates showed a bell-shaped dependence on dextran molecular mass and concentration, whereas maximal radius showed monotonic increase with both factors. Difference between aggregate and solution density was estimated using aggregate radius and sedimentation velocity and dextran solution viscosity, and was consistent across most molecular mass and concentration levels. This allowed to calculate the porosity of aggregates and to show that it monotonically decreased with the increase in the solution density, caused by the increase in the dextran concentration. The results provide insight into the RBC aggregation process in solutions of proteins of different size, reflecting various pathological conditions. The currently reported data can be potentially applied to specific pathophysiological conditions giving an interpretation that is not yet fully discussed in the literature.

The Impact of COVID-19 on Cellular Factors Influencing Red Blood Cell Aggregation Examined in Dextran: Possible Causes and Consequences

“…In addition to the cellular factors investigated in this study, the aggregation of erythrocytes in vivo is also influenced by plasma factors, specifically an increase in fibrinogen concentration and a rise in high-molecular-weight AOPPs. In our previous work, we demonstrated that the porosity of the formed aggregates decreases with increasing concentration of Dextran, regardless of its various molecular weights [98]. This suggests that in plasma, the effects described above may be magnified.…”

“…The image analysis method used in this study involves analyzing a time series of images to estimate the velocity and size of three-dimensional RBC aggregates. These procedures are described in more detail in the publication [98,102]. To analyze the aggregate movement, the time sequences of one-pixel-wide clippings for a given column of the sample from 50 consecutive images were composed (Figure 6).…”

Sialylated Glycan Bindings from SARS-CoV-2 Spike Protein to Blood and Endothelial Cells Govern the Severe Morbidities of COVID-19

“…In vitro, the addition of HMWD to blood likewise induced RBC aggregation [159,160] and did so as well when added to RBCs in PBS [161,162]. The same RBC disaggregating effect of LMWD was observed in vitro [163], possibly caused by competitive binding to RBCs that limited bridging between adjacent RBCs by larger molecules.…”