RED-CELL MEMBRANE STIFFNESS IN IRON-DEFICIENCY

  • 1 January 1983
    • journal article
    • research article
    • Vol. 62  (1) , 99-106
Abstract
The purpose of this study was to characterize red blood cell (RBC) deformability by Fe deficiency. RBC deformability was measured to ektacytometry, a laser diffraction method for determining the elongation of suspended red cells subjected to shear stress. Isotonic deformability of RBC from Fe-deficient human subjects was consistently and significantly lower than that of normal controls. In groups of rats with severe and moderate dietary Fe deficiency, RBC deformability was also reduced in proportion to the severity of Fe deficiency. At any given shear stress value, deformability of resealed RBC ghosts from both Fe-deficient humans and rats was lower than that of control ghosts. However, increase of applied shear stress resulted in progressive increase in ghost deformation, indicating that ghost deformability was primarily limited by membrane stiffness rather than by reduced surface area-to-volume ratio. This was consistent with the finding that Fe-deficient cells had a normal membrane surface area. In addition, the reduced mean corpuscular Hb concentration (MCHC) and buoyant density of the Fe-deficient rat cells indicated that a high Hb concentration was not responsible for impaired whole cell deformability. Biochemical studies of rat RBC showed increased membrane lipid and protein crosslinking and reduced intracellular cation content, findings that are consistent with in vivo peroxidative damage. RBC from Fe deficient rats incubated in vitro with H2O2 showed increased generation of malonyldialdehyde, an end-product of lipid peroxidation, compared to control RBC. Peroxidation apparently could contribute in part to increased membrane stiffness in Fe-deficient RBC. This reduced membrane deformability may in turn contribute to impaired red cell survival in Fe deficiency.