title: Phenotypic variation of retinal pigment epithelium in age-related macular degeneration.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0009, USA.
authors.forename: Clyde
authors.initials: C
authors.lastname: Guidry
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Medeiros
authors.forename: Christine A
authors.initials: CA
authors.lastname: Curcio
mesh_terms: D000199:Actins / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D008268:Macular Degeneration / Q000378:metabolism / Q000473:pathology*; D008297:Male; D010641:Phenotype; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D000199:Actins; D005904:Glial Fibrillary Acidic Protein; D014746:Vimentin