Abstract
Purpose :
We postulated that the use of iPSC-derived mesoderm would result in replacement of both retinal endothelial cells and pericytes in areas of vasodegeneration. The purpose of the study was to determine the in vivo survival, homing and differentiation capacity of iPSC derived mesoderm following intravitreal administration in the ischemia/reperfusion injury model (I/R) and in db/db mice.
Methods :
iPSC-derived mesoderm cells were characterized by the absence of expression of stage-specific embryonic antigen (SSEA5-) and presence of VEGFR2 (KDR+), N-Neural cell adhesion molecule (NCAM+), and the Apelin receptor (APLNR+) and were named SSEA5-KNA+cells. SSEA5-KNA+ cells were labeled with Td-Tomato and administered by intravitreal injection to I/R mice (n=6) or db/db mice (n=15). After 1 week, I/R mice were euthanized and eyes were processed for immunohistochemistry. db/db mice eye underwent 2nd injections that were performed eight weeks apart. At four weeks, retinal function was assessed by electroretinography (ERG) and visual acuity through Optokinetic reflex (OKR). Retinal structure and morphology was evaluated through OCT.
Results :
SSEA5-KNA+ cells migrated from the vitreous and were detected in the retina at post-injection day 7 in the I/R model using IHC. In the db/db model, at 4 weeks post injection, fundus photography, fluorescein angiography and OCT did not detect any retinal toxicity or alteration in retinal structure due to the injection of cells. A significant higher mean (*p<0.05) scotopic a- (260 ± 19.50) µV and photopic b- (102 ± 3.31) µV amplitudes were noticed in iPSC injected eye compared with saline injected eyes scotopic a- (181±18.5) µV and photopic b- (70.22 ± 5.63) in age matched db/db mice. However, few iPSC derived cells differentiated to endothelial cells or pericytes at the time points examined.
Conclusions :
Our results suggest that human SSEA5-KNA+ cells can migrate from the vitreous and home to injured retinal vessels in the I/R model with only small numbers of cells differentiating to vascular cells. The paracrine effect of the iPSCs may likely be responsible for the improved retinal function observed in db/db mice.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.