Erythrocyte membrane deformability in patients with thalassemia syndromes

The purpose of this study was to measure the erythrocyte membrane's elasticity in patients with thalassemia syndromes. These syndromes have been well investigated regarding the problems associated with the hemoglobin solution. A few studies dealing with the whole cells' flexibility have also been published. However, there are extremely few studies regarding the elastic behaviour of the membrane of these cells which plays a significant role in the viability of these erythrocytes especially when they transverse the small capillaries of the spleen. The micropipette aspiration method was used for this purpose. Cells from patients with thalassemia syndromes were aspirated into micropipettes of internal diameter of 1.2-1.6 microns. The slope of the curve relating the length of the aspirated tongue to the negative pressure was measured to give the elastic shear modulus. This modulus was compared with the one of the normal cells. Inclusions (Heinz bodies) were produced artificially in normal cells and their elastic shear modulus was also measured. The results show that the elastic shear modulus measured in homozygous beta-thalassemia was 33% higher than the normal one. The elastic shear modulus in cells with artificial Heinz bodies was also higher than the normal one and its value increased with the number of the inclusion Heinz bodies. The elastic shear modulus in heterozygous beta-thalassemia was slightly higher than the normal one. The apparent stiffening of the membrane of the homozygous cells might be partially due to the "constraining effect" of the inclusions to the membrane's ability to deform freely.