RGD peptide-assisted vitrectomy to facilitate induction of a posterior vitreous detachment: A new principle in pharmacological vitreolysis

Abstract

Purpose. To evaluate a new concept in pharmacological vitreolysis by studying the efficacy of intravitreal RGD peptideassisted vitrectomy in facilitating the separation of the posterior cortical vitreous from the retinal surface in an animal model. Methods. Eight rabbits (16 eyes) received an intravitreal injection of 1 or 5 mg of RGD peptide in one eye and either RGE peptide (inactive control) or phosphate buffered saline in the fellow eye. After 24 hours, a pars plana vitrectomy with low aspiration (=30mmHg) was performed in an attempt to create a detachment of the posterior cortical vitreous. A masked observer performed pre- and postoperative indirect ophthalmoscopy and B-scan ultrasonography. Postoperative scanning electron microscopy evaluated the vitreoretinal surface in selected eyes. Two additional rabbits received intravitreal injections of RGD peptide in one eye (1mg and 5mg) and 1 mg of RGE peptide in the fellow eye to examine apoptosis of the retinal cells by TUNEL assay. Results. Based on postoperative ultrasound findings, six of the eight rabbits had a greater degree of posterior vitreous detachment in the RGD eye compared to the fellow eye (p = 0.03). The total number and the average number of detached quadrants in the group of RGD peptide eyes was twenty-three and 2.85 respectively compared to seven and 0.85 for the control fellow eyes (p = 0.02). Scanning electron microscopy confirmed the presence of postoperative posterior vitreous detachment. There was no evidence of retinal cell apoptosis in RGD injected eyes. Conclusion. RGD peptide-assisted vitrectomy facilitated posterior vitreous detachment in rabbit eyes, suggesting that RGD-containing peptides may prove to be effective adjuncts in producing posterior vitreous separation during vitreous surgery.