Abstract
Purpose: :
latent stem cell properties have been identified in radial Muller glial cells derived from adult chicken, zebrafish, rat, mammalian and post mortem human retina, spontaneously and/or after injury. ELM is constituted of junctionnal complexes between Muller cells and photoreceptor cells inner layer. CD 133 (Prominin-1) is a Pentaspan protein membrane stem cell marker of recent use, specific of primitive human, mammalian and mice haematopoetic and neural Progenitor cells, expressed during migration and division of cells using Wnt and Notch pathways.This study was designed to evaluate with CD 133 the PG properties of the human pathological retina in vivo.
Methods: :
one paraffin-embedded phtisic eviscerated human eye with RD complicated by anterior and posterior PVR was studied with light microscopy. One normal adult eye exenterated for orbital tumor and one normal eye of an 18 weeks human foetus served as controls. All cases were stained with H&E&S, and serial sections were immunostained for antibody against: CD133 (Prominin-1), Epithelial Growth Factor receptor (EGFr), Polyclonal Antibody Glial Fibrillary Protein (GFAP), and Neuron Specific Enolase (NSE).
Results: :
in normal 18 weeks human fetus eye: CD133 was exclusively expressed in ELM with continuous staining. EGFR, GFAP, and NSE expressions were all negative in the retinal neuroblastic layers of the fetal sensory retina. In control adult human retina: CD133 and EGFR were negative; very mild GFAP staining was present adjacent to ELM. NSE was strongly expressed at the neuronal level. In long standing RD with PVR: continuous staining of CD133 was found again in ELM, and in a few cells in the sensory retina. GFAP positive radial gliosis and reduction in NSE expression with neuronal loss were simultaneously present; erratic focal EGFr expression was observed.
Conclusions: :
CD133 (Prominin-1), a stem cells marker, is expressed at ELM level in the human fetal retina and in the adult human retina with DR and PVR, and is not expressed in the normal adult eye. ELM might recover fetal PG properties during pathological conditions in the human adult eye. This might confirm a major role of Muller cells to induce regeneration and to maintain homeostasis in the human retina in vivo.
Keywords: Muller cells • retinal detachment • regeneration