From stem cells towards neural layers: a lesson from re-aggregated embryonic retinal cells

Neuroreport. 2001 May 25;12(7):A39-46. doi: 10.1097/00001756-200105250-00001.


Cells from dissociated embryonic avian retinae have the capacity to re-aggregate in rotation culture and form cellular spheres reconstituting a complete arrangement of all retinal layers. This exquisite phenomenon is based upon in vitro proliferation of multipotent precursor stem cells and spatial organization of their differentiating descendants. The addition of soluble factors from cultured retinal pigmented epithelial (RPE) or radial glial cells is essential to revert inside-out spheres (rosetted retinal spheres) into correctly laminated outside-out spheres (stratified spheres). Such complete restoration of a laminated brain tissue by cell re-aggregation has been achieved only for the embryonic avian retina, but not the mammalian retina, nor for other brain parts. This review summarises the history of the re-aggregation approach, presents avian retinal re-aggregate models, and analyses roles of the RPE and Müller cells for successful retinal tissue regeneration. It is predicted that these results will become biomedically relevant, as stem cell biology will soon open ways to produce large amounts of human retinal precursors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Cell Aggregation / drug effects
  • Cell Aggregation / physiology*
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology*
  • Cells, Cultured / cytology
  • Cells, Cultured / drug effects
  • Cells, Cultured / metabolism
  • Chick Embryo / cytology
  • Chick Embryo / embryology*
  • Chick Embryo / metabolism
  • Growth Substances / metabolism
  • Pigment Epithelium of Eye / cytology
  • Pigment Epithelium of Eye / metabolism
  • Retina / cytology
  • Retina / embryology*
  • Retina / metabolism
  • Stem Cells / cytology*
  • Stem Cells / drug effects
  • Stem Cells / metabolism


  • Growth Substances