Surgical approach for transplantation of a photoreceptor precursors patch in a swine Commotio Retinae model

Abstract

Purpose : Commotio Retinae (CR) causes significant morbidity in our combat service members. Impact displaces the lens-iris diaphragm backwards, stretching and tearing ocular tissues secondary to transmission of hydraulic forces. The retina absorbs the energy of the shockwave resulting in photoreceptor (PR) injury.
Since pig eyes have structural similarities to human eyes, we used them to develop a surgical technique to expose the sclera for blunt retinal trauma and subretinal transplantation of a photoreceptor precursor (PRP)-patch.

Methods : Four eyes from two pigs were used. Posterior sclera was exposed by medial rectus disinsertion and scleral traction. A piece of cadaveric sclera was glued to the sclera to better diffuse the impact. A pressure assisted device was used to induce CR; the shock wave damaged the PR in the visual streak (cone rich area) of the pig retina. Two weeks later, dissociated pig iPSC-derived retinal organoids seeded on a honeycomb (HC)-patterned poly (glycerol sebacate) (PGS) micro scaffolds were surgically implanted in the subretinal space in the area of PR loss/damage. Follow up examinations were performed for up to 2 months with optical coherence tomography and angiography (OCT/OCTA), and fluorescein and indocyanine green angiography (FA/ICG).

Results : The use of a scleral patch helped limit the local impact damage and extended the PR damage area. Controlled retinal detachment was induced using 0.25% Healon in BSS, allowing the PRP-seeded PGS micro scaffold introduction in the subretinal space. The scaffolds were easily visualized by OCT, native RPE and inner neural retina pattern was also visible. No signs of breakdown of the blood retinal barrier were seen by FA/ICG, and the scaffolds didn’t block visualization of choriocapillaris by OCTA.

Conclusions : Our CR model induced PR damage in the pig visual streak area and allowed transplantation of a PRP scaffold patch. No inflammatory reaction was seen in control eyes (micro scaffolds alone) or eyes transplanted with a PRP-seeded scaffold. Longer follow ups are needed to evaluate PRP integration in the host retina.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.