Reaktion der Endothelzellen auf kurzzeitig physiologisch erhöhte hydrostatische Drücke und oxidativen Stress in vitro

Zusammenfassung

Hintergrund Im Rahmen der Pathogenese des Glaukoms wird die endotheliale Dysfunktion zunehmend diskutiert. Peripapilläre Blutungen sind diagnostisch wegweisend. Die Korrelation von Glaukomerkrankungen mit vaskulärem Dysregulationssyndrom ist eindeutig. Ziel dieser Studie ist es, die genaue Reaktion der Endothelzellen auf erhöhten hydrostatischen und oxidativen Stress zu untersuchen.

Material und Methoden In vitro wurden primär dissoziierte BMECs (brain microvascular endothelial cells) für 3 Tage normalem und leicht erhöhtem hydrostatischem Druck von 60 und 120 mmHg in einer Druckkammer ausgesetzt. Zusätzlich wurden sowohl druckbelastete als auch nicht druckbelastete Zellen oxidativem Stress in Form von geringen Konzentrationen H₂O₂ ausgesetzt. Ein Live/Dead Assay wurde durchgeführt, um die Zellviabilität zu messen. Morphologisch wurden die Zellen mit immunhistochemischer Aktinfärbung beurteilt.

Ergebnisse Interessanterweise zeigten die Endothelzellen sowohl unter 60 mmHg als auch unter 120 mmHg kein vermehrtes Absterben im Vergleich zu den Zellen ohne Belastung. Auch morphologisch zeigten sich keine großen Unterschiede. Gegenüber oxidativem Stress wurden alle Zellen schon bei kleinen Mengen geschädigt. Keinen Unterschied konnte man zwischen oxidativem Stress ohne vorherige Druckbelastung und oxidativem Stress mit vorheriger Druckbelastung von 120 mmHg für 3 Tage feststellen.

Schlussfolgerung Wir konnten keinen direkten Effekt in Form von vermehrtem Zelluntergang der Endothelzellen auf erhöhten hydrostatischen Druck feststellen. Allerdings zeigt die Reaktion auf die geringen Konzentrationen von oxidativem Stress, dass die Zellen im Rahmen der Pathogenese des Glaukoms doch in Mitleidenschaft gezogen werden. Der oxidative Stress scheint hier eine besondere Rolle zu spielen.

Abstract

Introduction Endothelial dysfunction has become a strongly discussed factor regarding glaucoma pathogenesis. In addition to peripapillary bleedings as signs of vascular damage, there is a definite correlation between glaucoma and vascular dysregulation syndrome. The aim of this study was to evaluate endothelial cell reaction to moderately elevated hydrostatic pressure and oxidative stress in vitro.

Methods In vitro, primarily dissociated brain microvascular endothelial cells (BMECs) were exposed to moderately elevated hydrostatic pressure (60 and 120 mmHg) in a special pressure chamber. Additionally, cells primarily exposed to pressure, and cells not exposed to pressure, were incubated with low amounts of H₂O₂. A live/dead assay was performed to evaluate cell viability. Immunohistochemical staining against actin was used for morphological evaluation.

Results Neither 60 nor 120 mmHg of elevated pressure had a viability changing effect on primary endothelial cells. Secondary, no big morphological changes could be discovered. However, against a low concentration of oxidative stress, BMECs showed high vulnerability. A difference in reaction to cells stressed with high pressure before could not be shown.

Conclusion Direct effects, in terms of higher vulnerability or morphological changes of moderately elevated high pressure on endothelial cells, could not be shown. However, the reaction to low amounts of oxidative stress indicates the involvement of endothelial cells in the pathogenesis of glaucoma and the special role of oxidative stress when referring to endothelial dysfunction in glaucomatous disease.

Schlüsselwörter

Endothelzellen - hydrostatischer Druck - oxidativer Stress

Key words

endothelial cells - oxidative stress - hydrostatic pressure

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