Written by Nicholi Avery
Edited by Carla Parsons
A clinical-grade retinal implant made of human #embryonic stem cell (#hESC)–derived RPE grown on a synthetic substrate has been developed by Kashani and team. The progressive binding disease that causes loss of the retinal pigment epithelium (RPE) of the eye is known as #Non-neovascular age-related macular degeneration (#NNAMD). Currently there are only preventative measures that can be taken but there is no effective treatment. Some preventative measures include quitting smoking and the use of specific nutritional supplements to reduce the risk of developing NNAMD. The implant was not only shown to be safe in a first-in-human phase 1 clinical trial in five patients with advanced NNAMD, but also well tolerated. Plausible therapeutic effects on visual clarity were reported in the experimental results, indicating that this approach may be beneficial for treating retinal disorders involving #RPE loss.
One hallmark of non-neovascular age-related macular degeneration is the dysfunction and loss of Retinal pigment epithelium (RPE) dysfunction. This pigmented layer of cells next to the retina serves as a pass-through between the light-sensitive photoreceptors of the retina and a layer of blood vessels, called the choroid, lying below. RPE replacement strategies, may delay disease progression or restore #vision according to clinical and histological studies. The U.S. Food and Drug Administration cleared phase1/2 of a prospective and interventional study to be conducted in subjects with advanced NNAMD to assess the safety and adequacy of a composite subretinal implant. The composite implant, termed the #California Project to Cure Blindness–#Retinal Pigment Epithelium 1 (CPCB-RPE1), consists of a polarized monolayer of human embryonic stem cell–derived RPE (hESC-RPE) on an ultrathin, synthetic parylene substrate designed to mimic Bruch’s membrane.
It reported an interventional timeline analysis of the phase 1 cohort consisting of five subjects. The four out of five subjects who received the composite implant showed improvements. Changes were consistent with hESC-RPE and host photoreceptor integration as shown by optical coherence tomography imaging. The implanted eyes showed no progression of #vision loss, one eye showed improvement by seventeen letters and two eyes showed improvements in fixation. Simultaneously the concurrent structural and functional findings indicate that CPCB-RPE1 could potentially improve visual function. Since there are no effective treatments the prospect for improvements even in the short term in some patients with severe vision loss as a result of NNAMD would be a significant improvement.
“A bioengineered retinal pigment epithelial monolayer for advanced, dry age-related macular degeneration.”
Science Translational Medicine 04 Apr 2018:
Vol. 10, Issue 435, eaao4097
“Retinal Pigment Epithelium: The Eye’s first Line of Defense Against Macular Degeneration.”
BrightFocus-funded Work at ARVO 2016 BrightFocus.