Abstract
Purpose:
We have demonstrated previously that intravitreal injection of adipose stromal cells (ASC) in the eyes of diabetic rats improved the retinal function. Well defined ASC population with highest safety and efficacy are needed to plan for future human clinical trials. Recently, CD146+ population of vascular pericytes have been recognized as potential utility in particular therapeutic areas. In this study, we aim to identify if CD146+ population of pericyte ASC have better ability to migrate and adhere to the areas of injury in retinal blood vessels and improve the retinal function in I/R model of retinopathy.
Methods:
Unilateral retinal I/R were done in adult Lewis rats by transiently elevating the intraocular pressure for 1h. After day 7 of reperfusion, the animals were randomized to receive intravitreal CD146+ ASC, CD146- ASC (10,000 cells/eye) or saline injections. After further 6-7 days, retinal function was assessed by Electroretinogram (ERG), retinal apoptosis and gliosis by confocal microscopy and retinal whole mounts after 2 months for ASC localization to retinal vasculature. In vitro, CD146 was knockdown by CD146 siRNA with Lipofectamine RNAiMAX transient transfection. A scratch wound-healing assay was used to test ASC migration and an adhesion assay that measures the adherence of ASC to Laminin quantified via crystal violet uptake.
Results:
Retinal I/R resulted in a significant reduction in “b” wave amplitude, which was significantly improved by CD146+ ASC compared with CD146- ASC at day-6 post injection and remained high at one month. Confocal microscopy performed on retinal whole mounts from injured eyes that received CD146+ ASC demonstrated increased localization and homing to the retinal vasculature in comparison to CD146- ASC. Immunocytochemistry confirmed decreased apoptosis and gliosis with CD146+ASC (P<0.05). In vitro, CD146- ASC demonstrated reduced ability to close wound as compared to CD146+ ASC at 12-hour post injury (P<0.05). Knocking down CD146 also significantly reduced adhesion to Laminin (P<0.05).
Conclusions:
Our results show that CD146+ ASC, via improved adhesion and migration, improves the function of retina and rescues I/R injury induced retinal degeneration. The data suggest that CD146 plays a vital role in ASC to be more effective at being incorporated into the retinal perivasculature that is damaged in ischemic retinopathy.