Artikel
Cisternal CSF of SAH-patients induces endothelial cytosolic calcium oscillation via endoplasmic reticulum Ca2+
-ATPase
Zisternaler Liqour von SAB-Patienten induziert zytosolische endotheliale Kalziumoszillationen via Ca2+-ATPase des endoplasmatischen Reticulums
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
Text
Objective
The delayed cerebral vasospasm after subarachnoid hemorrhage (SAH) is apparently a multifactorial process, including dysfunction of fibroblasts, smooth muscle cells and endothelium. The aim of the present study was to investigate whether cisternal ceobrospinal fluid is able to influence the endothelial cytosolic Ca2+ concentration after SAH.
Methods
As an experimental model HUVEC (human umbilical cord vein endothelial cells) were incubated with cisternal cerebrospinal fluid (CSF) of 8 patients with SAH. Four of these patients had cerebral vasospasm. In control experiments we used native CSF. HUVEC were loaded with the fluorescence Ca2+ indicator FURA-2. The emitted fluorescence light was collected with an inverted microscope attached to a video imaging system.
Results
Incubation of HUVEC with SAH-CSF provoked cytosolic Ca2+ oscillations in 6 of 8 cases. After perfusion with CSF sampled from patients with cerebral vasospasm (n=4) endothelial Ca2+ oscillations appeared immediately in all cases. The oscillation frequency was 0,27±0,016 min-1 (mean value±SEM; n=44 cells). In the presence of tapsigargin an inhibitor of endoplasmic reticulum (ER) Ca2+--ATPase, the oscillations ceased in all cases. In further experiments the ER inositol-triphosphate (IP3) receptor gated Ca2+-channels were blocked by xestospongin and the ryanodine-dependent Ca2+-channels by rayanidine. Neither xestospongin nor ryanodine leads to a relevant reduction of the Ca2+ oscillations-frequency. In control experiments with native CSF no oscillations were observed.
Conclusions
Cisternal SAH-CSF, especially from patients with cerebral vasospasms, is able to induce endothelial cytosolic Ca2+ oscillations. These oscillations can be blocked by tapsigargin and are not influenced by IP3- and ryanodine-dependent Ca2+-channel activity. This indicates that SAH-CSF direct impairs ER Ca2+--ATPase function possibly by attack of hydoxyl radicals on the ATP-binding site.