Human neural retinal transplants into retinitis pigmentosa: facts and controversy / Manuel del Cerro, David A. DiLoreto, Constancia del Cerro, Eliot S. Lazar

Human neural retinal transplants into retinitis pigmentosa: facts and controversy / Manuel del Cerro, David A. DiLoreto, Constancia del Cerro, Eliot S. Lazar

Purpose. To discuss the scientific facts and controversies surrounding human retinal transplantation. Methods. In January 1995, we began multicenter, phase I clinical studies to assess the safety of transplanting neural retina into the subretinal space of patients with advanced retinal degenerative disease. A total of 18 patients with retinitis pigmentosa and one patient with age-related macular degeneration were transplanted with a suspension of fetal neural retina (14 to 18 weeks gestational age). No patients received systemic immunosuppression. Patients underwent pre-operative and post-operative visual testing, that in the most recent cases included a newly developed test battery for low level vision, assessment of accurate projection of rays, visual acuity, ERG, and visual fields. Results. The longest follow-up to date has been 2.5 years on four patients. No evidence of inflammation, infection, overt rejection or compromise to the host eye was noted in any patients. There was one case of retinal detachment. In this patient, vision worsened from hand motion to light perception. Three patients showed a 4 to 10 fold increase in light sensitivity starting one to two months after transplantation. Two of these patients have since returned to their pre-operative baseline. Six patients have shown improvement in vision starting 4 to 6 months post-transplantation which has been sustained to date. Two of these patients developed the ability to undergo visual field testing. Conclusions. Safe and efficient delivery of neural retinal cells into the subretinal space of patients with advanced retinitis pigmentosa has been achieved. The results warrant further studies to quantify the possible benefits of neural retinal transplantation in patients suffering from retinal degenerative diseases. A variety of issues regarding human retinal transplantation is discussed.

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