Aims: 

Molecular mechanisms of cereberal vasospasm after subarachnoid hemorrhage (SAH) include specific modes of cell signaling like activation of NF-kB and VCAM-1 expression. The hypothesis of the present study is that cisternal cerebrospinal fluid (CSF) from patients after SAH may cause Ca²⁺-oscillations which induce these modes of vascular inflammation in an in-vitro model of human cerebral endothelial cells (HCEC).

Methods: 

HCEC were incubated with cisternal CSF from 10 SAH patients with proven cerebral vasospasm. The CSF was collected on days 5 and 6 after hemorrhage. Cytosolic Ca²⁺-concentrations and cell contraction as indicator of endothelial barrier function were examined by fura-2. Activation of NF-kB and VCAM-1 expression were measured by immunocytochemistry.

Results: 

Incubation of HCEC with SAH-CSF provoked cytosolic Ca²⁺-oscillations (0.310.09 min^-1), cell contraction, NF-kB activation and VCAM-1 expression, whereas exposure to native CSF had no significant effect. When endoplasmic reticulum (ER) Ca^2+--ATPase and ER inositol-triphosphate-(IP3) Ca²⁺-channels were blocked by thapsigargin or xestospongin the frequency of the Ca²⁺-oscillations was reduced significantly. In analogy to the reduction of Ca²⁺-oscillations frequency, the blockers impaired HCEC contraction, NF-kB activation and VCAM-1 expression.

Conclusions: 

Cisternal SAH-CSF induces cytosolic Ca²⁺-oscillations in HCEC that results in cellular constriction, NF-kB activation and VCAM-1 expression. The Ca²⁺-oscillations depend on the function of ER Ca^2+--ATPase and inositol-triphosphate-(IP₃) Ca²⁺-channels.