Fluid trapping of erythrocytes under hypoosmolar conditions

Abstract

125I albumin was used to assess the amount of trapped fluid after microhematocrit centrifugation of erythrocytes suspended in buffers of different osmolality. Surprisingly the total amount of trapped fluid per volume unit of packed erythrocytes decreased with decreasing osmolality of the suspending buffer despite erythrocyte swelling. However, if the contribution of the individual erythrocyte to the trapped fluid was calculated, the trapped fluid per erythrocyte did not change between 311 mosm/kg and 256 mosm/kg. For osmolalities below 256 mosm/kg a significant increase of trapped fluid was obtained. It is concluded that the packing ability of erythrocytes is not impaired in suspending fluid of moderate to severe infraphysiological tonicity. The daily clinical experience that considerable degrees of plasma hypoosmolality are tolerated in vivo without hemolysis or impairment of oxygen transport by erythrocytes may be explained by the excellent ability of shape adaptation of erythrocytes to each other and to other surfaces such as vascular endothelia. The method of trapped fluid determination might be of potential value as a complementary method in the evaluation of erythrocyte rheology if the amount of trapped fluid is related to the individual erythrocyte.

Tank-treading of swollen erythrocytes in shear flows

“…We emphasize that lowered plasma osmolarity is found in several clinical syndromes including inappropriate antidiuretic hormone secretion and diuretic therapy [10]. As reported in the earlier study [10], the swollen erythrocytes may, in general, produce some difficulties in the blood capillary or splenic passage but the aforementioned conditions are not associated with impairment of oxygen transport or hemolysis of clinical significance.…”

“…As reported in the earlier study [10], the swollen erythrocytes may, in general, produce some difficulties in the blood capillary or splenic passage but the aforementioned conditions are not associated with impairment of oxygen transport or hemolysis of clinical significance. It is of interest to note that swollen erythrocytes have been employed during the encapsulation of non-diffusible drugs into human erythrocytes (used for drug delivery and targeting) [11].…”

“…The cell swelling results from the decrease of the osmolarity of the surrounding fluid from its physiological value of 300 mO [9]. Lowered plasma osmolarity (and thus swollen erythrocytes) is found in several clinical syndromes including inappropriate antidiuretic hormone secretion and diuretic therapy [10]. In our work we have studied the tank-treading dynamics of swollen erythrocytes in shear flows with capillary number Ca = O (1) and small to moderate viscosity ratios 0.01 ≤ λ ≤ 2.75.…”

Effect of osmolality on erythrocyte rheology and perfusion of an artificial microvascular network

“…It has been shown that osmolalities below 250 mOsm/kg increase the sphericity of RBCs to a point, where the trapping of suspending medium between RBCs during centrifugation gradually increases, which leads to an overestimation of MCV. 26 This may explain the non-linear increase of MCV and decrease of MCHC at very low osmolalities shown in Figure 2 .…”

Determination of extracellular/intracellular fluid ratios from magnetic resonance images: Accuracy, feasibility, and implementation

“…This volume is registered by the microhematocrit as intracellular volume, but not in the NMR hematocrit. Trapped extracellular fluid has been experimentally demonstrated to compose 1.6-2% of the total cell volume at approximately 30% hematocrit using identical microhematocrit tubes, spinning times, and range of osmolalities as in this investigation (26). The corresponding values for this investigation are probably 1-2% higher at the range of hematocrits used here (27).…”