Analysis of the deformability of adhered cells by mean of digital image processing

DANIELI, VIRGINIA; D'ARRIGO, MABEL; RIQUELME, B

Cape Town, South Africa

Congreso; ISBT 2006; 2006

The objective of this work is to obtain cellular deformability parameters, using the flow chamber technique and the digital image processing in different adhesion state of erythrocyte. For this, we study the deformation of erythrocytes under the effect of a given shear stress using a flow chamber system in two erythrocyte (doublet) linked by monoclonal antibody anti-A by mean of the digital image processing. The doublet is introduced and fixed inside the flow chamber, and then put under the influence of different shear stress values by a controlled laminar flow during a definite time. As a consequence, the cells are deformed, acquiring an elliptical hydrodynamic shape. At different applied shear stress values, microscopical images are registered with a CCD camera adapted to an inverted microscope and connected to a digital video system. Then these images are digitally processed, measuring the geometrical dimensions adopted by cells during deformation process. Taking into account that deformation process occurs under restrictions of constant cellular volume and constant superficial area, the shape can only be described by one parameter that reflects the relationship between the mayor and minor ellipse’s axis. The erythrocyte deformability index (EDI) is defined as EDI = L – l / (L + l), where L and l are the mayor and minor axis length respectively. In the experiences, it was found a gradual rise of EDI values with a gradual rise of applied shear stress values in a linear dependence, whereas its slope is characteristic of each cell in a particular situation. Then, studying the relationship between stress and deformability, it was possible to characterize the viscoelastic behavior of the erythrocyte’s membrane in different adhesion situations, which are related with the adhesion force in each situation. This study could be useful important, because it can help to understand blood’s behavior in circulation and can provide new parameters and relevant information about some hematological pathologies related with the alteration in the cellular adhesion properties.