In:
Kidney and Blood Pressure Research, S. Karger AG, Vol. 37, No. 6 ( 2013), p. 567-578
Abstract:
〈 b 〉 〈 i 〉 Background/Aims 〈 /i 〉 〈 /b 〉 : Klotho deficiency results in excessive formation of 1,25(OH) 〈 sub 〉 2 〈 /sub 〉 D 〈 sub 〉 3 〈 /sub 〉 , accelerated ageing and early death. Moreover, klotho deficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca 〈 sup 〉 2+ 〈 /sup 〉 -activity ([Ca 〈 sup 〉 2+ 〈 /sup 〉 ] 〈 sub 〉 i 〈 /sub 〉 ), glucose depletion, hyperosmotic shock and oxidative stress. Klotho expression is decreased and 1,25(OH) 〈 sub 〉 2 〈 /sub 〉 D 〈 sub 〉 3 〈 /sub 〉 -formation enhanced by dehydration. The present study thus explored whether dehydration influences eryptosis. 〈 b 〉 〈 i 〉 Methods 〈 /i 〉 〈 /b 〉 : Blood was drawn from hydrated or 36h dehydrated mice. Plasma osmolarity was determined by vapour pressure method, plasma 1,25(OH) 〈 sub 〉 2 〈 /sub 〉 D 〈 sub 〉 3 〈 /sub 〉 and aldosterone concentrations using ELISA, and plasma Ca 〈 sup 〉 2+ 〈 /sup 〉 -concentration utilizing photometry. Erythrocytes were exposed to Ca 〈 sup 〉 2+ 〈 /sup 〉 -ionophore ionomycin (1 µM, 30 min), energy depletion (12 h glucose removal), hyperosmotic shock (500 mM sucrose added, 2 h) and oxidative stress (100 µM tert-butyl-hydroperoxide, 30 min) and phosphatidylserine exposure at the erythrocyte surface estimated from annexin V binding. 〈 b 〉 〈 i 〉 Results 〈 /i 〉 〈 /b 〉 : Dehydration increased plasma osmolarity and plasma 1,25(OH) 〈 sub 〉 2 〈 /sub 〉 D 〈 sub 〉 3 〈 /sub 〉 and aldosterone concentrations. Dehydration did not significantly modify phosphatidylserine-exposure of freshly drawn erythrocytes but significantly enhanced the increase of phosphatidylserine-exposure under control conditions and following treatment with ionomycin, glucose-deprivation, hyperosmolarity or tert-butyl-hydroperoxide. 〈 b 〉 〈 i 〉 Conclusions 〈 /i 〉 〈 /b 〉 : Dehydration sensitizes the erythrocytes to spontaneous eryptosis and to the triggering of eryptosis by excessive Ca 〈 sup 〉 2+ 〈 /sup 〉 -entry, energy depletion, hyperosmotic shock and oxidative stress.
Type of Medium:
Online Resource
ISSN:
1420-4096
,
1423-0143
Language:
English
Publisher:
S. Karger AG
Publication Date:
2013
detail.hit.zdb_id:
1482922-8
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