Osmotic fragility model for red cell populations

Abstract

A model that predicts the osmotic fragility curve of a red cell population is developed by relating the critical osmotic pressure to the size distribution of the cells, determined by resistive pulse spectroscopy. Two of the parameters involved, namely the normalized osmotic volume correction, B, and the swelling index, k, are previously determined from the experimental average properties of the population. From these values the critical volume of the cell is obtained, and is shown to be 6-12% larger than the first spherical volume, obtained from an independent experiment. A new parameter, n, a measure of the surface area distribution of the cells, is incorporated through a simple function that relates the critical volume to the size of the cells, and is theoretically shown to be linked to parameters k and B. The model is used to fit and interpret fragility data obtained in this laboratory for normal and sickle cell samples. From the values of n obtained for normal samples, the model predicts an essentially constant surface-to-volume ratio within an individual's cell population. For sickle cell samples, instead, the value of index n is negative, thereby supporting an increase in excess surface area as cell size decreases. Both findings are in agreement with direct observations reported in the literature. It is concluded that this set of parameters may be used to develop an index classification of blood disorders.

Individual Osmotic Fragility Distribution: A New Parameter for Determination of the Osmotic Properties of Human Red Blood Cells

“…The osmotic fragility test is also useful for diagnosis of certain haematological diseases, for example, haemolytic anaemia, hereditary spherocytosis, and elliptocytosis, glucose-6-phosphate dehydrogenase deficiency, and sickle cell anaemia, as well as for RBCs from uremic or diabetic patients [5, 6]. Low osmotic resistance may lead to intravascular haemolysis, which causes a reduction of the RBC life span [5, 7].…”

“…The relation between osmotic pressure and cell volume is expressed by the equation [6]:$\begin{array}{c}\frac{{{\displaystyle false\prod }}_{}}{{{\displaystyle false\prod }}_{\text{iso}}}=\frac{V_{\text{iso}}-b}{V-b},\end{array}$ where b is a part of the RBCs volume osmotically inactive and ∏ iso and V iso are the osmotic pressure and volume for the isotonic media and ∏ and V for hypotonic media. The critical osmotic pressure ∏ cj for an individual cell, j , and the critical volume V cj corresponding to it are rewritten in the following form [6]: $\begin{array}{c}\underset{c,j}{\overset{\ast }{{\displaystyle false\prod }}}=\frac{{{\displaystyle false\prod }}_{cj}}{{{\displaystyle false\prod }}_{\text{iso}}}=\frac{V_{\text{iso},\text{j}}-b_j}{V_{c,j}-b_j}.\end{array}$ A distribution of the critical volumes associated with the distribution of critical osmotic pressures is expected. The absolute values of osmotically nonresponsible water are about 3.57 and 0.33 g water/g dry mass in the haemoglobin solution and in the erythrocytes, respectively [10].…”

A Stopped Flow System with Hydrodynamic Injection for Red Blood Cells Osmotic Fragility Test: Possibility for Automatic Screening of Beta-thalassemia Trait

“…11,12 in various situations where the surface-to-volume ratio or Even though thalassemia patients have some red cells that are membrane physiology of the red cells is altered. [1][2][3] Elevated OF more fragile than normal, a larger portion is less fragile. 1 This (less resistant to hemolysis) has been reported to relate directly to may be due to the presence of some difficult-to-break cells, hereditary spherocytosis due to less pressure tolerance of the irregularly shaped cells, and abnormal cell membrane.…”

Efeito do exercício físico na estabilidade de membrana de eritrócitos

“…O teste de fragilidade osmótica é amplamente utilizado para elucidar a influência de diferentes fatores na propriedade osmótica de eritrócitos, tais como, tensão de cisalhamento, hemólise mecânica (Sowemimo-Coker, 2002), doenças (Bartosz, 1991;Massaldi, Richieri, & Mel, 1988), idade (de Freitas et al, 2014;), temperatura (Pribush et al, 2003, uso de medicamentos, estresse oxidativo ) e outros Paraiso et al, 2014;.…”

“…Estudar as propriedades da membrana dos eritrócitos é muito vantajoso, pois é fácil monitorar sua lise, sua membrana é facilmente isolada, sendo livre de contaminação de outras células e organelas, e também porque as alterações da membrana refletem nas propriedades da célula em sua totalidade (Massaldi et al, 1988;.…”