Effects of elevated pressure and hypoxic conditions on select retinal cell functions

Date
2011
Authors
Coronado, Ramon E.
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Abstract

The present in vitro project was motivated by the need to elucidate cellular- and molecular-level aspects of glaucoma, a potentially blinding eye disease often associated with elevated intraocular pressure and retinal hypoxia. The rationale of the present study was the fact that in vivo elevated intraocular pressure compresses the vasculature of the eye with resultant reduced blood flow, leading to reduction of oxygen and nutrient transport to various eye tissues. Under these conditions, it is unavoidable that, the eye tissues are affected both at the cellular- and molecular-levels. The nature and extent of these effects, however, are not known. The present in vitro study focused on the effects of elevated pressure, hypoxia and the combination of these conditions on select cells from the retina.

One of the most important findings of the present study was the evidence that the various cell types tested responded differently when exposed to the conditions of elevated pressure (DeltaP = 35 mm Hg) and hypoxia (5% O 2). Specifically, human retinal astrocyte (HRA) proliferation was reduced when exposed to the elevated pressure, but not affected when exposed to hypoxia after five consecutive days. Bovine Choroidal Endothelial Cell (BCEC) proliferation was reduced only when these cells were exposed to elevated pressure in combination with hypoxia after four consecutive days. Bovine retinal microvessel endothelial cell (BRMEC) proliferation was enhanced when these cells were exposed to combined elevated pressure and hypoxia after four consecutive days.

Another important finding of the present study was the evidence that the mitogenic/angiogenic bioactivity of vascular endothelial growth factor (VEGF) was part of the underlying mechanism responsible for the observed enhanced proliferation of BRMEC when these cells were exposed to the combined elevated pressure and hypoxia conditions tested.

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Keywords
Astrocytes, Endothelial, Hypoxia, Hypoxic, Pressure, Retinal
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Department
Biomedical Engineering