Human adipose stem cell derived pericytes protect against retinal vasculopathy in vivo

Abstract

 

Purpose

 

This work demonstrates that intravitreally injected adipose-derived stem cells (ASCs) can potentially be used to protect against the damaging effects of diabetic retinopathy (DR). David Cogan defined retinal pericyte loss as a characteristic of early DR pathology in the 1960s. Yet there remain no viable strategies to replace these cells once lost or rendered dysfunctional by diabetes. Here, we demonstrate the ability of ASCs to differentiate into functional pericytes, both in vitro and in multiple in vivo models of retinal vasculopathy, and show they can serve both a protective and reparative role for the retinal vasculature.

 

Methods

 

We collected the stromal vascular fraction from human adipose tissue and isolated ASCs by serial passaging. We injected ASCs intravitreally either before or after five days of hyperoxia in the oxygen-induced retinopathy (OIR) model to assay ASC impact on retinal vascular retention or regrowth, respectively. ASCs were also subjected to treatment with transforming growth factor β (TGFβ), to investigate the impact of TGFβ preconditioning on ASC-endothelial cell interaction both in vitro and in vivo, as well as ASC contractility. Finally, Akimba mice were treated with murine ASCs to measure their impact on DR progression.

 

Results

 

When injected intravitreally, ASCs invest into the retinal microvasculature, often adopting the location, morphology, and marker expression characteristic of pericytes. ASC-treated retinas demonstrated increased vascular stability compared to sham injected controls in the OIR model, with ASCs displaying pericyte marker expression two months after injection. TGFβ preconditioning enhances ASC stabilization of endothelial cells and increases their cellular contractility to a degree comparable to retinal pericytes. TGFβ pretreatment also enhances ASC vascular stabilization in the OIR model. Mouse ASCs conferred a 79% reduction in capillary dropout in the DR Akimba model.

 

Conclusions

 

Adipose tissue represents an abundant and readily accessible source of adult vascular progenitors, which may be used to generate pericytes for regenerative DR therapy. When injected intravitreally, ASCs migrate to and stabilize the retinal vasculature in three pre-clinical retinopathic animal models. TGFβ enhances ASC pericyte function both in vitro and in vivo.

 

 

Injected ASCs adopting pericyte location and morphology on a retinal vessel (bar = 20 μm).

 

Keywords: 721 stem cells • 499 diabetic retinopathy • 706 retinopathy of prematurity