Phenotypic variation of retinal pigment epithelium in age-related macular degeneration

Invest Ophthalmol Vis Sci. 2002 Jan;43(1):267-73.


Purpose: To determine whether retinal pigment epithelium (RPE) in eyes with age-related macular degeneration (ARMD) express vimentin and alpha smooth muscle actin (alphaSMA), two cytoskeletal proteins associated with phenotypic variation in culture.

Methods: Six eyes with late ARMD and three age-matched control eyes were preserved in buffered 4% paraformaldehyde and cryosectioned at 10 microm. Stages of RPE morphology and pigmentation were assessed by the Alabama Age-Related Macular Degeneration Grading System. Vimentin, alphaSMA, and glial fibrillary acidic protein (GFAP) expression was detected by indirect immunofluorescence. These results were compared with regional variations in disease severity.

Results: RPE changes in ARMD included acquired expression of vimentin, but alphaSMA-positive cells were rare. GFAP expression increased in Müller cells in the neural retina in association with RPE changes and photoreceptor degeneration.

Conclusions: The initial stages of RPE changes in eyes with ARMD mimic those reported for cultured RPE cells. The absence of alphaSMA-positive cells in regions of RPE atrophy suggests that RPE are lost rather than persist in a dedifferentiated state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Aged
  • Aged, 80 and over
  • Female
  • Fluorescent Antibody Technique, Indirect
  • Glial Fibrillary Acidic Protein / metabolism
  • Humans
  • Macular Degeneration / metabolism
  • Macular Degeneration / pathology*
  • Male
  • Phenotype
  • Pigment Epithelium of Eye / metabolism
  • Pigment Epithelium of Eye / pathology*
  • Vimentin / metabolism


  • Actins
  • Glial Fibrillary Acidic Protein
  • Vimentin