title: South-east asian ovalocytic (SAO) erythrocytes have a cold sensitive cation leak: implications for in vitro studies on stored SAO red cells.
abstract: South-east Asian ovalocytosis (SAO) results from the heterozygous presence of an abnormal band 3, which causes several alterations in the properties of the erythrocytes. Although earlier studies suggested that SAO erythrocytes are refractory to invasion in vitro by the malarial parasite Plasmodium falciparum, a more recent study showed that fresh SAO cells were invaded by the parasites, but became resistant to invasion on storage because intracellular ATP was depleted more rapidly than normal. Here we show that SAO red cells are much more leaky to sodium and potassium than normal red cells when stored in the cold. This leak was much less marked when the cells were stored at 25 or 37 degreesC. Incubation for 3.5 h at 37 degreesC of cold-stored SAO red cells did not restore sodium and potassium to normal levels, probably because the depleted ATP level in cold-stored SAO red cells is further reduced with incubation at 37 degreesC. The increased leakiness of SAO red cells is non-specific and extends to calcium ions, taurine, mannitol and sucrose. These results suggest that SAO red cells undergo a structural change on cooling. Since many of the reports describing altered properties of SAO red cells have used cells which have been stored in the cold, these results need re-evaluation using never-chilled SAO red cells to assess whether the cells have the same abnormal properties under in vivo conditions.
authors.affiliation: Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Bruce
authors.forename: S M
authors.initials: SM
authors.lastname: Ring
authors.forename: K
authors.initials: K
authors.lastname: Ridgwell
authors.forename: D M
authors.initials: DM
authors.lastname: Reardon
authors.forename: C A
authors.initials: CA
authors.lastname: Seymour
authors.forename: H M
authors.initials: HM
authors.lastname: Van Dort
authors.forename: P S
authors.initials: PS
authors.lastname: Low
authors.forename: M J
authors.initials: MJ
authors.lastname: Tanner
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D001793:Blood Preservation; D002463:Cell Membrane Permeability; D003080:Cold Temperature; D015925:Cryopreservation; D004612:Elliptocytosis, Hereditary / Q000097:blood*; D004910:Erythrocyte Membrane / Q000502:physiology; D004912:Erythrocytes / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D008353:Mannitol / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012964:Sodium / Q000032:analysis; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013395:Sucrose / Q000032:analysis; D013654:Taurine / Q000032:analysis
chemical_list: D013654:Taurine; D008353:Mannitol; D013395:Sucrose; D000255:Adenosine Triphosphate; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium