Deformability of Erythrocytes is maintained after Autologous Cell Salvage in Orthopedic Surgery

Background and Objective: Prerequisite for oxygen transport to the tissue is the ability of erythrocytes to change from a discoid into an elongated form in order to pass microvessels. Cell salvage is highly recommended to decrease blood loss and to avoid allogeneic transfusions in perioperative bleeding. The purpose of our study was to assess deformability of erythrocytes at re-transfusion. Materials and Methods: After ethics committee approval and informed consent, blood was withdrawn from the autotransfusion system (Xtra, Sorin, Germany) of 24 patients undergoing joint arthroplasty 6 hours after cell salvage initiation. Deformability curves, elongation indices (EI) obtained at increasing shear stress (SS) were assessed by using Laser Optical Rotational Red Cell Analysis (LORRCA). Results: Erythrocytes showed the typical sigmoid EI/SS curve with a mean maximum elongation index (EImax) of 0.593 ± 0.034 and mean half-maximal deformation (SS ½) of 1.186 ± 0.387 Pa. Irregular curve shapes and high variability in EI occurred at shear stress < 3 Pa. Recalculation of outcome parameters resulted in higher values (EImax 0.610 ± 0.035; SS ½ 1.562 ± 0.346 Pa). Conclusion: Erythrocytes after autologous cell salvage are not stiff but elongate in response to shear stress. Erythrocytes showed the typical EI/SS-curve of human red cells, which indicates that the cells are able to uptake the hydrodynamic forces that act on them during the measurement. Further research is needed to investigate the effect of cell salvage processing on erythrocytes from patients with pre-existing hematological disorders.

Evaluation of Antioxidant Capacity of Plant Extracts Using Flow Cytometry

This study is aimed to evaluate the inhibitory effect of natural extracts on reactive oxygen species (ROS) in human red cells (RBCs) under oxidative stress and to demonstrate the importance of using natural extracts from plants in the fight against oxidative stress. Therefore, seven nonalcoholic extracts were tested at several dilutions, in order to prove their antioxidant activity using flow cytometry. The level of intracellular hydrogen peroxide significantly decreased when the cells were coincubated with different extracts, the values of the Mean Fluorescence Intensity (MFI) ranging from 206 to 3702, compared with 3872, the value obtained in case of H2O2-treated cells (RBCs + H2O2). All the tested extracts demonstrated a good inhibition, Melissa officinalis L. extract showed a greater percentage of hydrogen peroxide inhibition even at the last dilution (94.70% (D-a)�.85.76% (D-e)). The results suggest the importance of the investigated natural extracts to combat oxidative stress.

Towards microfluidic-based depletion of stiff and fragile human red cells that accumulate during blood storage

In this study, the effects of prolonged storage on several biophysical properties of red blood cells (RBCs) were investigated.