Temperature sensitivity of suicidal erythrocyte death.
BACKGROUND
Fever and hyperthermia are frequently associated with anaemia. Under most clinical conditions, they are considered to be two mutually independent clinical consequences of a common cause. The present study explored the possibility that anaemia results from temperature-sensitive suicidal erythrocyte death or eryptosis. Eryptosis is characterised by cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) exposure at the erythrocyte surface. It is triggered by increase in the cytosolic Ca(2+) activity on the one hand and by ceramide formation on the other.


METHODS
Annexin V-binding was utilised to disclose PS exposure, forward scatter to analyse cell volume, Fluo 3 fluorescence to estimate cytosolic Ca(2+) activity, binding of fluorescent antibodies to determine ceramide abundance and a luciferin/luciferase-based assay to measure the cytosolic ATP concentration.


RESULTS
Graded increases in temperature from 37 to 41 degrees C decreased the forward scatter and stimulated annexin V-binding of human erythrocytes. The effect was accompanied by increased cytosolic Ca(2+) activity, decrease of the cellular ATP content and a moderate rise in ceramide formation. The effect of hyperthermia on annexin V-binding was significantly blunted by the leukotriene receptor CysLT1 antagonist cinalukast (1 microM).


CONCLUSIONS
Hyperthermia stimulates Ca(2+) entry into erythrocytes leading to cell shrinkage and PS exposure. As PS-exposing erythrocytes are rapidly cleared from circulating blood, the eryptosis during hyperthermia may cause anaemia.
Föller
Michael
M
Department of Physiology, University of Tübingen, Tübingen, Germany.
Braun
Manuel
M
Qadri
Syed M
SM
Lang
Elisabeth
E
Mahmud
Hasan
H
Lang
Florian
F
D000255:Adenosine Triphosphate / Q000032:analysis; D017209:Apoptosis / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology; D002518:Ceramides / Q000276:immunology / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004912:Erythrocytes / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006358:Hot Temperature; D006801:Humans; D020024:Leukotriene Antagonists / Q000494:pharmacology; D010718:Phosphatidylserines; D018000:Receptors, Peptide / Q000378:metabolism / Q000502:physiology; D013844:Thiazoles / Q000494:pharmacology
D015220:Calcium Channels; D002518:Ceramides; D020024:Leukotriene Antagonists; D010718:Phosphatidylserines; D018000:Receptors, Peptide; D013844:Thiazoles; C080707:annexin V receptor; C071436:cinalukast; D000255:Adenosine Triphosphate; D002118:Calcium