Abstract
Purpose :
The pathological events of age-related macular degeneration (AMD) are characterized by degenerative processes involving the photoreceptor cells, retinal pigment epithelium (RPE), the Bruch’s membrane and choroidal alterations. To examine the interactions between photoreceptor cells and RPE cells ex vivo complex models are required. The aim of this study was to investigate the beneficial effects of a primary RPE cell co-culture or conditioned medium from these cells on neural retina explants.
Methods :
Porcine neural retina explants were co-cultured with primary RPE cells (ppRPE) or with medium derived from RPE cells (medium). Individually cultivated neural retina explants served as controls (control). After eight days, RT-qPCR (n=6-7/group) and immunohistology (n=7-10/group) were performed to analyze the amount, condition, and expression of photoreceptors, synapses, macroglia, microglia, complement factors, and pro-inflammatory cytokines (e.g., Il-1β, Il-6, Tnf-α).
Results :
The presence of ppRPE cells preserved the expression of photoreceptor specific markers (opsin: p=0.016, rhodopsin: p=0.027), whereas the medium group only showed a preservation of opsin+ cells in immunohistology (p<0.001), but not with RT-qPCR. Only minor differences between the three groups were noted in regard to microglia, Iba1+ cell counts were lower in the ppRPE group (p=0.042). Increased Il-6 levels were noted in ppRPE and medium samples, while Tnf-α was only upregulated in the ppRPE group and Il-1β was elevated in medium samples. In regard to synaptic activity, PSD95+ area was increased in ppRPE (p=0.024) and medium samples (p=0.043).
Conclusions :
In conclusion, a co-culture of ppRPE cells and neural retina seems to have a beneficial effect, preserving photoreceptors and synaptic activity in vitro. These organ culture models could be used to mimic the complex interactions between the retina and RPE cells and gain further insights into neurodegenerative pathomechanisms occurring in retinal disease like AMD.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.