Photodisruption of the Inner Limiting Membrane Promotes Retinal Engraftment of Stem-Cell Derived Retinal Ganglion Cells

Purpose: The purpose of this study is to address the challenge of limited donor retinal ganglion cell (RGC) migration into the retina after transplantation, which is largely due to donor neuron accumulation at the inner limiting membrane (ILM). We present a minimally invasive technique, ILM photodisruption, to locally ablate the ILM and thereby promote RGC engraftment. Methods: ILM photodisruption uses indocyanine green as a photosensitizer, which is delivered to the ILM and activated with ultra-short laser pulses. This process generates vapor nanobubbles (VNBs) that, upon collapse, create localized disruptions in the ILM. In this study, we finetuned this technology in bovine and postmortem human organotypic retinal explants to generate patterned ILM pores. To assess the impact of these photodisruption patterns on RGC transplantation, we applied induced pluripotent stem cell (iPSC)-derived RGCs to the ILM surface and co-cultured them for 7 days. Using advanced microscopy and spatial metric tools, we assessed donor RGC survival, spreading, and neurite localization. We compared ILM photodisruption to a current standard method of enzymatically digesting the ILM. Results: ILM photodisruption was highly effective in creating pores in both the bovine ILM and the thicker, more complex human ILM. In contrast, collagenase treatment had no effect on the human ILM. Both collagenase and ILM photodisruption significantly promoted donor RGC survival, enhanced cell spreading, and resulted in more neurites that extended deeper into the retina. Conclusions: Our findings demonstrate that ILM photodisruption can overcome a key barrier in RGC replacement therapy and, as such, may help advance vision restoration strategies for glaucoma.