Gradual morphogenesis of retinal neurons in the peripheral retinal margin of adult monkeys and humans

Abstract

The adult mammalian retina has been for long considered to lack neurogenerative capacity. However, retinal stem/progenitor cells which can originate retinal neurons in vitro have been recently reported in the ciliary body of adult mammals. Here we have explored the possibility of retinal neurogenesis occurring in vivo in adult monkeys and humans. We have found the presence of cells expressing molecular markers of neural and retinal progenitors in the non-laminated retinal margin and ciliary body pars plana of mature primates. By means of imunohistochemistry and electron microscopy we have also observed photoreceptors and other retinal cell types in different stages of morphological differentiation along the peripheral retinal margin. These findings allow us to extend to primates the idea of neurogenesis aimed at retinal cell turnover throughout life.