Effects of osmolality and solutes on the morphology of red blood cells according to three-dimensional refractive index tomography

Abstract

Phosphate-buffered saline (PBS) and Alsever’s solution (AS) are frequently used as media in blood-related studies, while 0.9% normal saline (NS) is frequently used in transfusion medicine. Despite the frequent use, the effects of these solutions on the shape and volume of red blood cells (RBCs) have not been reported. We collected blood samples from five healthy adults and used three-dimensional refractive index tomography to investigate the changes in the morphology of RBCs caused by changes in osmolality and solutes at the single-cell level. After diluting 2 μL of RBCs 200-fold with each solution (PBS, AS, and 0.9% NS), 40 randomly selected RBCs were microscopically observed. RBC shape was measured considering sphericity, which is a dimensionless quantity ranging from 0 (flat) to 1 (spherical). RBCs in plasma or AS showed a biconcave shape with a small sphericity, whereas those in 0.9% NS or PBS showed a spherical shape with a large sphericity. Moreover, we confirmed that sodium chloride alone could not elicit the biconcave shape of RBCs, which could be maintained only in the presence of an osmotic pressure-maintaining substance, such as glucose or mannitol. Although 0.9% NS solution is one of the most commonly used fluids in hematology and transfusion medicine, RBCs in 0.9% NS or PBS are not biconcave. Therefore, as the debate on the use of NS continues, future clinical studies or applications should consider the effect of glucose or mannitol on the shape of RBCs.

Deformability of mouse erythrocytes in different diluents measured using optical tweezers

“…The shape of erythrocytes is highly influenced by osmotic pressure and solutes. 47 Our experimental results indicate that these exogenous diluents have difficulty achieving good match with mouse erythrocytes, resulting in damage to the membrane structure of mouse erythrocytes. Indeed, additive solutions that include citrate or mannitol, such as citrate-phosphate-dextrose-adenine (CPDA-1), saline-adenine-glucose-mannitol (SAGM), and additive solution-3 (AS-3), have membrane-protective functions.…”

Clinical implication of changes in serum cations and anions on clinical severity in sickle cell disease: A case–control study in a tertiary center

“…Plasma albumin is also attributed to RBC membrane stabilization and the shape and volume of RBCs. 8,24,25 Low albumin also depicted a significant inverse relation with the disease severity score (►Table 5). A cutoff value of 0.63 mmol/L (4.2 g/dL) showed a sensitivity of 88.9% for the crisis state (►Table 6 and ►Fig.…”

“…Changes in plasma osmolality, either due to fluid overload during intravenous therapy or kidney dysfunction, leads to RBC dehydration, intracellular HbS concentration, and polymerization in the deoxygenated state, further promoting sickling. 1,3,8 The extracellular tonicity alters the RBCs' biomechanical properties; thus, managing these patients with suitable intravenous fluids of appropriate volume and flow rate would most likely improve the rheological properties and reduce the frequency of crisis events. 9 Presently, Hb and fetal Hb (HbF) is routinely measured to assess the clinical course.…”

Swelling Behavior of Novel Hydrogels Produced from Glucose-Based Ionic Monomers with Varying Cross-Linkers

“…We furthermore decided to continue all further swelling experiments in PBS (pH = 7.4) since we aim to study the use of our hydrogels as drug delivery systems in the future. PBS provides a constant pH value and is comparable to the osmolarity and ion concentration of the human organism …”