Abstract
The present study was designed to evaluate the influence of calcium (Ca)1, regulated membrane attached hemoglobin (Hbm) on the viscoelastic properties of density fractionated human RBC membranes. (Ca)1 of RBC was elevated using ionophore A23187 (10μM); mechanical properties of RBC membranes were determined via micropipette technique. Salient results included: 1) a 300% increase in membrane viscosity of aged cells following ionophore treatment corresponding to elevated Hbm levels; 2) no change in membrane viscosity and Hbm, levels of young cells after ionophore exposure; 3) no dependence between elastic shear modulus and intracellular calcium concentration. 4) Comparison to osmotically shrunk cells reveals an additional calcium concentration dependent association of hemoglobin to the membrane. This implies nembrane mechanical properties are independent from the intracellular viscosity. Our results appear relevant to hemolytic diseases characterized by elevated (Ca)1, (e.g. sickle cell anemia) and to age associated changes in deformability. Supported by DFG Fr 752/1-1 u. 1-2 by NIH grants HL 15162 and HL 15722 and Dy AHA-GLAA award 5371G.
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Friederichs, E., Meiselman, H. & Linderkamp, O. 132 CALCIUM REGULATED MEMBRANE-ATTACHED HEMOGLOBIN AND MECHANICAL PROPERTIES OF DENSITY FRACTIONATED ERYTHROCYTES HEMBRANES: IMPLICATIONS FOR HEMOLYTIC DISEASES AND RBC AGEING. Pediatr Res 28, 299 (1990). https://doi.org/10.1203/00006450-199009000-00156
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DOI: https://doi.org/10.1203/00006450-199009000-00156