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Abstract #19331 Published in IGR 9-3
Acute retinal ganglion cell injury caused by intraocular pressure spikes is mediated by endogenous extracellular ATP
Resta V; Novelli E; Vozzi G; Scarpa C; Caleo M; Ahluwalia A; Solini A; Santini E; Parisi V; Di Virgilio FEuropean Journal of Neuroscience 2007; 25: 2741-2754
See also comment(s) by George Lambrou •
Elevated intraocular pressure may lead to retinal ganglion cell injury and consequent visual deficits. Chronic intraocular pressure increase is a major risk factor for glaucoma, a leading blinding disease, and permanent visual deficits can also occur following acute pressure increments due to trauma, acute glaucoma or refractive surgery. How pressure affects retinal neurons is not firmly established. Mechanical damage at the optic nerve head, reduced blood supply, inflammation and cytotoxic factors have all been called into play. Reasoning that the analysis of retinal neurons soon after pressure elevation would provide useful cues, we imaged individual ganglion cells in isolated rat retinas before and after short hydrostatic pressure increments. We found that slowly rising pressure to peaks observed in trauma, acute glaucoma or refractive surgery (50-90 mmHg) did not damage ganglion cells, whereas a rapid 1 min pulse to 50 mmHg injured 30% of these cells within 1 h. The severity of damage and the number of affected cells increased with stronger or repeated insults. Degrading extracellular ATP or blocking the P2X receptors for ATP prevented acute pressure-induced damage in ganglion cells. Similar effects were observed in vivo. A short intraocular pressure transient increased extracellular ATP levels in the eye fluids and damaged ganglion cells within 1 h. Reducing extracellular ATP in the eye prevented damage to ganglion cells and accelerated recovery of their response to light. These data show that rapid pressure transients induce acute ganglion cell injury and unveil the causal role of extracellular ATP elevation in such injury.
Dr. L. Galli-Resta, Istituto di Neuroscienze CNR, Via G. Moruzzi 1, 56100 Pisa, Italy. galli@in.cnr.it
Classification:
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
8.4 Refractive surgical procedures (Part of: 8 Refractive errors in relation to glaucoma)
