ENHANCEMENT OF RETINAL RECOVERY BY CONJUGATED DEFEROXAMINE AFTER ISCHEMIA-REPERFUSION

Purpose. Although toxic to the retina in its native form, the iron che lator deferoxamine (DFO) shows no apparent retinal toxicity when bound to hydroxyethyl-starch (HES). Conjugation of DFO does not alter its i ron binding properties. Once bound, iron is no longer active in the pr oduction of toxic oxygen intermediates. This investigation seeks to de termine whether HES-conjugated DFO (HES-DFO) protects against ischemia -reperfusion injury in the retina. Methods. Retinal ischemia was induc ed in cats, pretreated with HES-DFO, using both the vascular ligation and the increased intraocular pressure models. Retinal recovery tvas m onitored by electroretinography. Fundal fluorescein angiography was pe rformed in treated and untreated animals after ischemia-reperfusion. R esults. Our results indicate that pretreatment with an intravenous bol us of HES-DFO, significantly enhances recovery of the postischemic b-w ave and decreases fluorescein leakage after ischemia-reperfusion. Conc lusions. HES-DFO improves recovery of the neural retina after ischemia -reperfusion. It also maintains the integrity of the blood-retinal bar rier. The protective effect of HES-DFO on the blood-retinal barrier is consistent with its intravascular confinement. That HES-DFO results i n protection of the neural retina underscores the importance of the bl ood-retinal barrier as a mediator of ischemia-reperfusion injury. HES- DFO may have a role in the early management of ischemic retinal diseas e both as an iron chelator and as a blood-retinal barrier protector.