Artikel
Subarachnoid hemorrhage induces cytosolic Ca2+-oscillations in human cerebrovascular endothelial cells
Induktion von zytosolischen Ca2+-Oszillationen in humanen zerebralen Endothelzellen nach subarachnoidaler Blutung
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: Molecular mechanisms of vascular inflammation include specific modes of cell signaling like endothelial cytosolic Ca2+-oscillations that activate NF-κB, lead to VCAM-1 expression and cell contraction. The goal of this study was to investigate this pathophysiological sequence of events in vitro on human cerebral endothelial cells (HCEC) which were exposed to cisternal cerebrospinal fluid (CSF) from patients, after aneurysmal subarachnoid hemorrhage (SAH).
Methods: HCEC were incubated with cisternal CSF from 10 SAH patients with cerebral vasospasm. CSF was collected on the 5th and 6th day after SAH. Cytosolic Ca2+-concentrations and cell contraction were examined by Fura-2 microfluometry. Thapsigargin, xestospongin and ryanidine were used to block endoplasmic reticulum (ER) ATPase, inositol-triphosphate (IP3) and ryanidine-dependent Ca2+-channels, respectively. NF-κB and VCAM-1 activation was measured immunocytochemically.
Results: Incubation of HCEC with SAH-CSF provoked cytosolic Ca2+ oscillations (0.31±0.09 min-1) and cell contraction. No Ca2+-oscillations were detected after exposure to native CSF. The presence of thapsigargin or xestospongin significantly reduces the frequency of Ca2+ oscillations and cell contraction whereas ryanodine had no influence. Incubation of HCEC with SAH-CSF induced NF-κB activation and VCAM-1 expression, which were significantly reduced by thapsigargin or xestospongin
Conclusions: Cisternal CSF from SAH patients induces intercellular gap-formation, NF-κB activation and VCAM-1 expression as key factors of vascular inflammation. This is due to cytosolic Ca2+oscillations in HCEC as a result of a dysfunction of the ER.