Affiliations: Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA | Department of Operative Techniques and Surgical Research, Medical and Health Science Centre, Faculty of Medicine, University of Debrecen, Debrecen, Hungary | Medical Department IV, Klinikum Darmstadt, Darmstadt, Germany | Department of Physiology, Akdeniz University Faculty of Medicine, Antalya, Turkey
Note: [] Address for correspondence: Dr. Herbert J. Meiselman, Department of Physiology and Biophysics, Keck School of Medicine, 1333 San Pablo Street, MMR 626, Los Angeles, CA 90033, USA. Tel.: +1 323 442 1268; Fax: +1 323 442 2283; E-mail: meiselma@usc.edu.
Abstract: Prior reports describing the effects of lanthanum (La3+) on red blood cells (RBC) have focused on the effects of this lanthanide on cell fusion or on membrane characteristics (e.g., ion movement across membrane, membrane protein aggregation); the present study explores its rheological and biophysical effects. Normal human RBC were exposed to La3+ levels up to 200 μM then tested for: (1) cellular deformability using a laser-based ektacytometer and an optical-based rheoscope; (2) membrane viscoelastic behavior via micropipettes; (3) surface charge via micro electrophoresis. La3+ concentrations of 12.5 to 200 μM caused dose-dependent decreases of deformability that were greatest at low stresses: these rheological changes were completely reversible upon removing La3+ from the media either by washing with La3+-free buffer or by suspending La3+-exposed cells in La3+-free media (i.e., viscous dextran solution). Both membrane shear elastic modulus and membrane surface viscosity were increased by 25–30% at 100 or 200 μM. As expected, La3+ decreased RBC electrophoretic mobility (EPM), with EPM inversely but not linearly associated with deformability; changes of EPM were also completely reversible. These results thus indicate novel aspects of RBC cellular and membrane rheological behavior yet raise questions regarding specific mechanisms responsible for La3+-induced alterations.
Keywords: Deformability, electrophoresis, lanthanum, red blood cell, membrane
Journal: Biorheology, vol. 44, no. 5-6, pp. 361-373, 2007
