A2E, a byproduct of the visual cycle

Vision Res. 2003 Dec;43(28):2983-90. doi: 10.1016/s0042-6989(03)00475-9.


A substantial portion of the lipofuscin that accumulates with age and in some retinal disorders in retinal pigment epithelial (RPE) cells, forms as a consequence of light-related vitamin A recycling. Major constituents of RPE lipofuscin are the di-retinal conjugate A2E and its photoisomers. That the accretion of A2E has consequences for the cell, with the adverse effects of A2E being attributable to its amphiphilic structure and its photoreactivity, is consistent with evidence of an association between atrophic age-related macular degeneration (AMD) and excessive lipofuscin accumulation.

Publication types

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

MeSH terms

  • Atrophy / metabolism
  • Humans
  • Light / adverse effects
  • Lipofuscin / metabolism*
  • Macular Degeneration / metabolism*
  • Pigment Epithelium of Eye / metabolism*
  • Pigment Epithelium of Eye / radiation effects
  • Pyridinium Compounds / metabolism*
  • Retina / metabolism
  • Retina / pathology*
  • Retinaldehyde / metabolism
  • Retinoids / metabolism*
  • Vitamin A / metabolism


  • A2-E (N-retinylidene-N-retinylethanolamine)
  • Lipofuscin
  • Pyridinium Compounds
  • Retinoids
  • Vitamin A
  • Retinaldehyde