Abstract
Purpose :
To investigate the impact of flexural modulus and vertical stabilization of the scaffolds on the ability of the human iPS-derived retinal pigment epithelial cells (hiPS-RPE) to phagocytose photoreceptor outer segments.
Methods :
RPE cells from five different hiPS-RPE lines and ARPE-19 cells were cultured to confluence on human Bruch’s membrane (hBM; flexural modulus: 1.6-2.44 Mpa) explants and tissue culture inserts with a 10 µm-thick transparent polyester (PET; flexural modulus: 2.8-3.5 Gpa) membrane. One week after the confluence, 6.0 mm grafts were cut and transferred to another dish. These circular grafts were either stabilized on a photopolymerizable biogel or left unstabilized within the culture medium. Grafts were maintained within a culture medium for 4 hours in the presence of FITC-labeled human photoreceptor outer segments (108 per/ml). At the end of the incubation period, cells were collected after trypsinization. Flow cytometric analyses were carried out to determine the number of DRAQ5-stained viable cells that phagocytosed FITC-labelled human photoreceptor outer segments.
Results :
hiPS-RPE exhibited better phagocytosis of photoreceptor outer segments compared to ARPE-19 cells on both substrates regardless of the graft stabilization (15.6±4.4% vs 6.8±2.4% on stabilized hBM, p=0.004; 24.1±5.5% vs 5.8±2.0% on unstabilized hBM, p=0.0001; 56.8±16.0% vs 5.7±1.6% on stabilized PET membranes, p=0.008 and 78.4±9.8% vs 29.2±8.7% on unstabilized PET membranes, p=1.5x10-6). Phagocytic ability of the hiPS-RPE cells was better if hBM (p=0.008) and PET membrane (p=4.6x10-6) were not stabilized. hiPS-RPE demonstrated better phagocytosis on PET membranes compared to hBM regardless of the stabilization of the substrate. (p<0.001)
Conclusions :
Flexural modulus of the hiPS-RPE graft can modulate the function of the grafted RPE cells. hiPS-RPEcells exhibit better phagocytosis on PET membranes compared to hBM grafts.
This is a 2021 ARVO Annual Meeting abstract.