Autologous choroidal endothelial cell replacement using Laminin based hydrogels for the treatment of AMD.

Abstract

Purpose : Loss of choroidal endothelial cells (CEC) is an early feature of age related macular degeneration (AMD). While replacement of CECs has the potential to delay and/or prevent death of the overlying RPE and neural retina, injection of therapeutic cells as an unsupported single cell suspension typically results in poor donor cell retention, survival and integration. The purpose of this study was to develop an injectable self healing hydrogel system suitable for delivery of iPSC derived CECs to treat early AMD.

Methods : An injectable self healing hydrogel system composed of laminin, chitosan, and dextran was synthesized based on aldehyde and amine reversible chemistry. Gelation kenetics were evaluated via rheometry and cellular compatibility was evaluated via a live dead assay. To demonstrate cellular survival and integration in vivo, cell laden hydrogels were injected into the suprachoroidal space of SRG rats (n=24). Donor cell survival and xenograft integration were analyzed using fundus photography, OCT, and IHC.

Results : Three injectable hydrogels were formulated by varying the composition of precursors and different isoforms of Laminin (LN111, LN 421 and LN121). All of the developed hydrogels showed excellent cell survival in vitro. At 1-week post-injection, we found that LN111 and LN121 gels were well tolerated inciting minimal immune reaction as determined by microglial/macrophage (IBA1) staining (Figure 1A-C). Following suprachoroidal injection of cell laden hydrogels, widespread choroidal endothelial cell survival and engraftment was detected in the choroid of SRG rats (Figure 1D-E).

Conclusions : In this study, we successfully developed laminin based self healing injectable hydrogels with desirable mechanical and biocompatibility profiles. Using these hydrogels we were able to successfully deliver CECs into the suprachoroidal space of rats with excellent cell retention and survival. These findings act as proof of principle for an early intervention strategy designed to repopulate the choroid of patients with AMD.

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

 

Figure 1: A-C) Suprachoroidal injection of laminin-based hydrogels and evaluation of immune response in rat. Gel, which is encircled in red, is autofluorescent. OCT (D) and fluorescence fundus (E) photos demonstrating successful injection and persistence of GFP-positive human CECs following injection into the suprachoroidal space of SRG rats using the hydrogel.