Retinal neuroprotection against ischemic injury mediated by intraocular gene transfer of pigment epithelium-derived factor.
OBJECTIVE
To determine whether intraocular gene transfer of pigment epithelium-derived factor (PEDF) protects the retina from ischemia-reperfusion injury.


METHODS
Four days before induction of pressure-induced ischemia, Lewis rats received intravitreous injection of 3 x 10(9) particles of an adenovirus vector expressing PEDF (AdPEDF.11) in one eye and 3 x 10(9) particles of an empty adenovirus vector (AdNull.11) in the contralateral eye. Seven days after reperfusion, eyes were enucleated and processed for morphometric analysis. Apoptotic cells stained by TdT-dUTP terminal nick-end labeling (TUNEL) in the retina were counted 12 hours after initiation of reperfusion. Retina levels of PEDF were measured by enzyme-linked immunosorbent assay.


RESULTS
PEDF levels in retinal homogenates from eyes receiving AdPEDF.11 injection were well above the background levels in the untreated baseline and control eyes (P = 0.04). Retinal thickness was preserved in AdPEDF.11-treated eyes. Retinal cell density was significantly greater in the ganglion cell layer (GCL; P = 0.014), inner nuclear layer (INL; P = 0.008), and outer nuclear layer (ONL; P = 0.008) of AdPEDF.11-treated eyes compared with the corresponding layers in AdNull.11-treated eyes. AdNull.11-treated eyes also had significantly more TUNEL-positive cells in these layers than AdPEDF.11-treated eyes (P < 0.05).


CONCLUSIONS
Adenoviral vector-mediated intraocular expression of PEDF significantly increases cell survival after ischemia-reperfusion injury of the retina. The protective effect may result from inhibition of ischemia-induced apoptosis. This study provides proof of concept for a gene transfer approach directed at interrupting programmed cell death induced by retinal ischemic insult.
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D002452:Cell Count; D002470:Cell Survival; D019610:Cytoprotection / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins; D005260:Female; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D020287:In Situ Nick-End Labeling; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012164:Retinal Diseases / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology*; D015843:Serpins / Q000235:genetics* / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
D005136:Eye Proteins; D009414:Nerve Growth Factors; D011506:Proteins; D015843:Serpins; D000099174:Pigment Epithelium-Derived Factor