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Alteration of the mechanical properties of sickle cells by repetitive deoxygenation: role of calcium and the effects of calcium blockers
Author(s) -
Nash G. B.,
Boghossian S.,
Parmar J.,
Dormandy J. A.,
Bevan D.
Publication year - 1989
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1989.tb07692.x
Subject(s) - deoxygenation , calcium , chemistry , pharmacology , biophysics , medicine , biochemistry , biology , catalysis
Summary. The formation of dense, poorly deformable sickle cells was studied by subjecting pre‐separated, less dense cells to repeated deoxygenation and reoxygenation for 15 h. In the presence of Ca (2 mmol/l), this process caused the number of irreversible sickled cells to increase five‐fold, mean cell haemoglobin concentration to increase by 13% and cellular potassium to decrease by 22%. Also, red cell filterability through 5 μm filter pores was greatly worsened. These effects decreased but were not totally abolished when the extracellular Ca concentration was lowered to zero or 0·01 mmol/1. If a high K medium was used (135 mmol/l), cell swelling rather than shrinkage occurred. Swelling also occurred if ouabain was added to the incubation. The Ca‐channel blockers nitrendipine and nisoldipine had different effects. Nitrendipine. in the range 10 −7 ‐10 −5 mol/l, was partially protective against all the induced changes, but nisoldipine was not protective at 10 −8 or 10 −6 mol/l. Thus, deterioration in the properties of sickle cells appears to be linked to Ca‐dependent potassium loss during repeated sickling and is inhibited by nitrendipine.