title: Apolipoprotein E epsilon4 offers protection against age-related macular degeneration.
abstract: BACKGROUND
  In many previous studies, age-related macular degeneration (ARMD) has been linked to a variety of different risk factors. The publications have debated whether apolipoprotein E (apoE) epsilon4 serves as a potential protective factor in the development of the disease. Other studies have classified the behavior of this protein in different pathologies, including Alzheimer's disease (AD) and cardiovascular disease. The general behavior of the epsilon4 isoform of ApoE is different than the predominant epsilon3 isoform.
  
  
  OBJECTIVE
  We propose that the general characteristics and molecular behavior of apoE epsilon4 cause it to be a protective factor against the development of ARMD by preventing cumulative effects of oxidative retinal damage. EVALUATION OF HYPOTHESIS: Review of the literature related to ARMD and ApoE, using OVID as our main database, led to the development of several theories regarding ApoE epsilon4's behavior compared to epsilon3 and potential explanation of its protective characteristics. CONSEQUENCES OF HYPOTHESIS: We relate these theories to the potential behavior of ApoE epsilon4 in other situations including choroidal neovascularization, Alzheimer's Disease (AD), cardiovascular disease, herpes simplex virus infection, and smoking.
  
  
  CONCLUSIONS
  The potential implications of this theory could be used as a branching point for further studies that examine the role of the different apoE isoforms, in relation to the other risk factors for ARMD.
authors.affiliation: Department of Ophthalmology, LSU Health Sciences Center, New Orleans, LA 70112-2234, United States.
authors.forename: Duncan A
authors.initials: DA
authors.lastname: Friedman
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Lukiw
authors.forename: James M
authors.initials: JM
authors.lastname: Hill
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D053327:Apolipoprotein E4 / Q000378:metabolism*; D016208:Databases, Factual; D006801:Humans; D008268:Macular Degeneration / Q000517:prevention & control*; D008954:Models, Biological; D020011:Protective Agents / Q000378:metabolism*
chemical_list: D053327:Apolipoprotein E4; D020011:Protective Agents