Characterization of conditioned media collected from aged versus young human eye cups

To characterize secretion of in situ retinal pigment epithelium (RPE) from healthy, aged adult, age-related macular degeneration (AMD) adult, and fetal donor eyes and to assess the impact on retinal survival in vitro.

Conditioned medium (CM) was collected from adult and fetal donor eyes and analyzed for trophic factor composition by multiplex ELISA. Trophic factor receptor occupancy was calculated to evaluate differences in trophic factor concentrations. RPE trophic factor mRNA expression was quantified by real-time PCR. Retina-preserving activity of the collected CM was evaluated using degenerating porcine retina in vitro.

Compared with CM from adult donors, AMD donor CM contained a significantly higher concentration of brain-derived neurotrophic factor (BDNF), whereas fetal donor CM contained significantly higher concentrations of hepatocyte growth factor (HGF) and pigment epithelium-derived factor (PEDF). No consistent correlation was found between trophic factor mRNA expression and protein secretion. Non-RPE components of the RPE-Bruch's membrane-choroid-sclera complex were major contributors of vascular endothelial growth factor-A (VEGF-A). CM of fetal donors was significantly better than CM of adult or AMD donors at improving the survival of degenerating porcine retina.

RPE cells of adult and fetal eyes have significantly different trophic factor production capabilities, which correlated with changes in preservation of porcine retina. Combined with trophic factor receptor occupancy calculations, these data may implicate HGF and PEDF as key factors promoting the preservation of retinal structure and function.