Potassium Loss and Cellular Dehydration of Stored Erythrocytes following Incubation in Autologous Plasma: Role of the KCI Cotransport System


Cattedra di Medicina Interna Istituto di Patologia Medica Policlinico Borgo Roma I–37134 Verona (Italy)


We studied the regulation of cell volume and cation content in erythrocytes stored at 4°C under blood bank conditions for various lengths of time and subsequently incubated in autologous plasma at 37°C for 4 or 24 h. Cell swelled during storage at 4°C whereas marked K+ loss and cell shrinkage were observed when erythrocytes were incubated at 37°C in autologous plasma. The cell shrinkage was inhibited only by the K+Cl- cotransport-specific inhibitor, [(dihydroindenyl)oxy] alkanoic acid, and not by other specific inhibitors of cation transport systems such as ouabain (Na+-K+ ATPase pump), bumetanide (Na+-K+-Cl- cotransport) or carbocyanine (Ca++-activated K+ channel). Acidification and swelling of the erythrocytes are well known to be able to activate the K+Cl- cotransport; such conditions, which were demonstrated to occur during the storage, could lead to activation of the K+Cl- cotransport in reinfused cells. These data strongly support the evidence that K+Cl- cotransport plays a role in K+ loss and dehydration of stored erythrocytes, when incubated in autologous plasma.