Importance of Choriocapillaris Replacement in Therapeutic Strategies for Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is a progressive disease of the retina, characterised by the degeneration of several cell layers, including the choriocapillaris (CC), retinal pigment epithelium (RPE) and photoreceptors (PR). Because of this, cell replacement therapies have the potential to treat AMD. Previous research has predominantly focussed on the development of a transplantable pluripotent stem cell-derived RPE monolayer, owing to RPE degeneration early in AMD. However, there is now increasing evidence for CC atrophy early in the pathogenesis of AMD. Given the crucial role of the CC in retinal homeostasis, there is significant potential to expand research into CC replacement with the hope of advancing current cell therapies. The RPE and CC have a highly interconnected relationship, and thus, the replacement of one of these cell layers while the other remains dysfunctional may not be optimal for the long-term rescue of vision in AMD. Therefore, one approach would be to replace both the RPE and CC as a combined cell therapy. Here, we outline the importance of CC in health and disease, as well as potential considerations when building a tissue-engineered CC-like vascular network, with a particular focus on pericytes.