title: Intravitreal administration of multipotent mesenchymal stromal cells triggers a cytoprotective microenvironment in the retina of diabetic mice.
abstract: BACKGROUND
  Diabetic retinopathy is a common complication of diabetes and the leading cause of irreversible vision loss in the Western world. The reduction in color/contrast sensitivity due to the loss of neural cells in the ganglion cell layer of the retina is an early event in the onset of diabetic retinopathy. Multipotent mesenchymal stromal cells (MSCs) are an attractive tool for the treatment of neurodegenerative diseases, since they could differentiate into neuronal cells, produce high levels of neurotrophic factors and reduce oxidative stress. Our aim was to determine whether the intravitreal administration of adipose-derived MSCs was able to prevent the loss of retinal ganglion cells in diabetic mice.
  
  
  METHODS
  Diabetes was induced in C57BL6 mice by the administration of streptozotocin. When retinal pro-damage mechanisms were present, animals received a single intravitreal dose of 2 × 10(5) adipose-derived MSCs or the vehicle. Four and 12 weeks later we evaluated: (a) retinal ganglion cell number (immunofluorescence); (b) neurotrophic factor levels (real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA)); (c) retinal apoptotic rate (TUNEL); (d) retinal levels of reactive oxygen species and oxidative damage (ELISA); (e) electrical response of the retina (electroretinography); (f) pro-angiogenic and anti-angiogenic factor levels (RT-qPCR and ELISA); and (g) retinal blood vessels (angiography). Furthermore, 1, 4, 8 and 12 weeks post-MSC administration, the presence of donor cells in the retina and their differentiation into neural and perivascular-like cells were assessed (immunofluorescence and flow cytometry).
  
  
  RESULTS
  MSC administration completely prevented retinal ganglion cell loss. Donor cells remained in the vitreous cavity and did not differentiate into neural or perivascular-like cells. Nevertheless, they increased the intraocular levels of several potent neurotrophic factors (nerve growth factor, basic fibroblast growth factor and glial cell line-derived neurotrophic factor) and reduced the oxidative damage in the retina. Additionally, MSC administration has a neutral effect on the electrical response of the retina and did not result in a pathological neovascularization.
  
  
  CONCLUSIONS
  Intravitreal administration of adipose-derived MSCs triggers an effective cytoprotective microenvironment in the retina of diabetic mice. Thus, MSCs represent an interesting tool in order to prevent diabetic retinopathy.
authors.affiliation: Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Ezquer
authors.affiliation: Departamento de Oftalmología, Facultad de Medicina, Universidad de Chile, Av. Independencia 1027, Santiago, Chile.
authors.forename: Cristhian A
authors.initials: CA
authors.lastname: Urzua
authors.affiliation: Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile.
authors.forename: Scarleth
authors.initials: S
authors.lastname: Montecino
authors.affiliation: Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile.
authors.forename: Karla
authors.initials: K
authors.lastname: Leal
authors.affiliation: Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile.
authors.forename: Paulette
authors.initials: P
authors.lastname: Conget
authors.affiliation: Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile. eezquer@udd.cl.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ezquer
mesh_terms: D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured; D019610:Cytoprotection; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D003930:Diabetic Retinopathy / Q000628:therapy*; D005260:Female; D058449:Intravitreal Injections; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000502:physiology; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D009414:Nerve Growth Factors / Q000378:metabolism; D018384:Oxidative Stress; D012160:Retina / Q000378:metabolism / Q000473:pathology
chemical_list: D009414:Nerve Growth Factors
keywords: Cytoprotection; Diabetes; Diabetic retinopathy; Mesenchymal stem cells; Microenvironment; Multipotent mesenchymal stromal cells; Prevention; Retinal ganglion cells