Artikel
Ventricular hemorrhage causes necrosis of human astrocytes by a cytosolic Ca2+-overload and mitochondrial damage
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Veröffentlicht: | 16. September 2010 |
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Gliederung
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Objective: Ca2+ is a cofactor of many intracellular processes including apoptosis and necrosis. This study’s hypothesis was that bloody CSF from patients after intraventricular hemorrhage (IVH) may cause a Ca2+-rise which induces a mitochondrial dysfunction that results in necrosis in a in-vitro model of human cerebral astrocytes.
Methods: Human astrocytes were incubated with CSF from patients with IVH. In control experiments native CSF was used. Single cell cytosolic Ca2+-concentrations were measured by fura-2 microfluometry. Three blockers were used: Cyclosporin A, APB and suramine that block mitochondrial permeability transition pores (MPTP), endoplasmic reticulum IP3 sensitive Ca2+-channels and ATP-sensitive PY2-rezeptor, respectively. Apopotois and necrosis were evaluated by staining with Hoechst-3342 and propidium iodide, respectively.
Results: Incubation of astrocytes with bloody-CSF provoked an initial Ca2+ peak that was followed by a slow but long lasting Ca2+-rise over the observation period of 60 min. This was also true, when the extracellular Ca2+ was bounded by EDTA. Incubation of the astrocytes with bloody-CSF induced necrosis but not apoptosis. APB and suramin reduced both significantly the Ca2+-rise and the rate of necrosis. Cyclosporin A did not influence the Ca2+-rise but reduced significantly the rate of necrosis.
Conclusions: Bloody CSF induces a Ca2+-overload that leads to necrosis but not apoptosis in human astrocytes via activation of the ATP-sensitive PY2-receptor and Ca2+ release from IP3-dependent intracellular Ca2+-stores. The necrosis is due to Ca2+-dependent opening of MPTP resulting in breakdown of mitochondrial homoeostasis.