New Challenging Approach In The Treatment Of Diabetic Retinopathy: Intravitreal Co-transplant Of Human Amnion Epithelial And Mesenchymal Stem Cells As Neuroprotective And Anti-apoptotic Mediators

Abstract

Purpose: : Amniotic Membrane (AM) is an attractive source of stem cells and growth factors with features that embrace wide differentiation potential, paracrine activities and immunomodulatory and neuroprotective properties. In consideration of this, these cells represent prime candidates a new regenerative/reparative approach in the treatment of diabetic retinopathy (DR). In this study we investigated the effect of co-transplant of human amnion epithelial and mesenchymal stem cells as possible tools for the treatment of DR due to these cells’ feature to release neurotrophic and anti-apoptotic growth factors in the vitreous.

Methods: : Mesenchymal stem cells (MSCs) were isolated from stromal layer of AM, whereas Amniotic Epithelial Cells (AEC) were isolated and expanded from epithelial layer of AM. These populations were characterized and assessed for differentiation potential. Molecular expression of neurotrophic and anti-apototic factors were studied: in particular nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) were considered. MSCs and AECs were pre-stained with Vybrant DiO fluorescent dye, injected in the vitreous chamber and tracked in an animal model (Lewis Rats) in order to assess the achievability of the technique.

Results: : Clinical examinations were realized using Micron III retinal imaging system(Phoenix Research Laboratories, Inc.). Amnion derived stem cells displayed considerable in vitro expansion and differentiation potential; molecular analysis evidenced remarkable expression of neurotrophic factors such as NGF and BDNF, with differences related to the source. Histological evaluation evidenced absence of flogosis after the incjection. Amnion transplanted cells, marked with the fluorescent dye, were found in a region proximal to the vitreo-retinal interface: there they exert a paracrine neuroprotective effect and contribute to repopulate the retina.

Conclusions: : The combination of MSCs’ secretion of anti-apoptotic and neurotrophic factors, with the differentiation potential of AEC permitted the development of new challenging approach in the treatment of DR.

Keywords: diabetic retinopathy • neuroprotection • growth factors/growth factor receptors