Membrane transport of Na and K and cell dehydration in sickle erythrocytes.
The cellular concentration of Hb S plays a central role in the kinetic of Hb S polymerization and cell sickling. Blood of patients with homozygous sickle cell (SS) anemia contains a variable fraction of cells which are markedly dehydrated and have increased Hb S concentration. Since a decrease in cellular Hb S concentration reduces Hb S polymerization and sickling, the study of the processes leading to sickle cell dehydration has important pathophysiological and therapeutic implications. Sickle cell dehydration is due to cellular loss of K and Cl. K loss in sickle cells can take place via either the Ca(2+)-activated K+ channel, or the K-Cl cotransport, or the combined effect of oxidative damage and deformation of the red cell membrane. Inhibitors of K transport through these pathways could be used to prevent dehydration of sickle cells in vivo, provided that they can be administered safely.
Brugnara
C
C
Department of Pathology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
D000755:Anemia, Sickle Cell / Q000097:blood*; D001692:Biological Transport; D002118:Calcium / Q000097:blood; D002712:Chlorides / Q000097:blood; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004913:Erythrocytes, Abnormal / Q000378:metabolism*; D006801:Humans; D009566:Nitrates / Q000097:blood; D010100:Oxygen / Q000097:blood; D011188:Potassium / Q000097:blood*; D015221:Potassium Channels / Q000378:metabolism; D012964:Sodium / Q000097:blood*; D014882:Water-Electrolyte Balance
D002712:Chlorides; D009566:Nitrates; D015221:Potassium Channels; D012964:Sodium; D011188:Potassium; D010100:Oxygen; D002118:Calcium