Abstract
Purpose:
In USA, nearly 50% of low-birth weight infants develop Retinopathy of prematurity (ROP). Current strategies for the treatment of ROP including cryotherapy are not effective in all patients and there is unmet need for identification of new therapies. We have shown that cells derived from the stromal fraction of adipose tissue (ASC) are pluripotent stem cells, reside in perivascular niche, possess functional and phenotypic overlap with pericytes and improve ischemia reperfusion in-vivo. In this study, we hypothesized that ASC may stabilize vasculature and therapeutically rescue ROP features.
Methods:
To analyze the effect of ASC, postnatal day-7 neonatal immune compromised NSG mice along with nursing mothers were subjected to oxygen induced retinopathy (OIR). At p12 mice were randomized to receive human ASC (10,000 cells/eye/2μL) into the left eye and saline into the right eye. At p17, mice were euthanized; retinal wholemounts were imaged by confocal microscopy and mRNA expression by qRT-PCR. In-vitro human retinal endothelial cells (HREC) subjected to hypoxia were co-cultured with ASC and apoptosis was measured by Capase-3 and viability by WST-1 assay.
Results:
Retinal wholemounts obtained from OIR mice, revealed a dramatic decrease in total tubelength (assessed by MetaMorph angiogenesis tube formation module) compared to age-matched control mice, was significantly increased in OIR mice that received ASC (25395±1600 v/s 34453±1919μm; p<0.001). In addition, OIR mice that received ASC demonstrated a 2-3 fold decrease in mouse specific ICAM-1, MCP-1 and an increase in VEGF and VEGFR2 compared to OIR mice that received saline. In-vitro, HREC formed capillary networks with ASC in direct contact co-culture, as evidenced by vWF staining. Immunostaining with αSMA suggested that HREC were able to direct differentiation of the ASC along a pericytic lineage potentially capable of stabilizing vasculature. Furthermore, HREC subjected to hypoxia demonstrated a significant decrease in cell viability and increased capase-3 staining, while those co-cultured with ASC alleviated apoptosis and improved cell viability.
Conclusions:
Our findings suggest that, ASC impart vasculoprotection under hypoxic/inflammatory conditions and may have therapeutic potential in treating ischemic conditions and pathological angiogenesis. Further characterization of ASC will provide vital information about vasculoprotective nature of these cells.
Keywords: 706 retinopathy of prematurity •
721 stem cells •
687 regeneration