title: Clearance of dying ARPE-19 cells by professional and nonprofessional phagocytes in vitro- implications for age-related macular degeneration (AMD).
abstract: OBJECTIVE
  Failure of retinal pigment epithelial (RPE) cells and macrophages to engulf different dying cells in the retina may result in accumulation of debris and development of age-related macular degeneration (AMD). The dynamics and influence of different treatments on this clearance process can be studied in vitro using human ARPE-19 cells and macrophages as phagocytes modelling dry and wet type of AMD, respectively.
  
  
  METHODS
  Death through extracellular matrix detachment using polyHEMA-coated surfaces (anoikis) and UV irradiation (apoptosis) was induced in ARPE-19 cells. Two-coloured phagocytic assays were performed to quantify the amount of dying cells phagocytes engulfed (flow cytometry) and for visualization (fluorescent and scanning electron microscopy). The effect of phosphatidylserine inhibition with recombinant annexin-V and glucocorticoid (triamcinolone) treatment on the phagocytic process was tested.
  
  
  RESULTS
  The clearance of anoikic and apoptotic cells by nondying ARPE-19 cells over 8 hr of co-incubation increased over time (at 8 hr, over 53% and 35% of the phagocytes contained engulfed dying cells, respectively). The human macrophages engulfed the anoikic and apoptotic ARPE-19 cells with seven and four times lower capacity, respectively. Phosphatidylserine appearance on the dying cells did not affect, but triamcinolone treatment enhanced the phagocytosis of the dying cells by macrophages.
  
  
  CONCLUSIONS
  ARPE-19 cells are more efficient in clearing anoikic than UV-induced apoptotic cells. Macrophages are less efficient in the clearance process than ARPE-19 cells. The present model can be used for studying both dry and wet type of AMD in vitro and for testing different pharmacological aspects affecting this disease.
authors.affiliation: Department of Ophthalmology, Medical and Health Science Center, University of Debrecen, Hungary. gokip@indi.dote.hu
authors.forename: Goran
authors.initials: G
authors.lastname: Petrovski
authors.forename: Erika
authors.initials: E
authors.lastname: Berényi
authors.forename: Morten C
authors.initials: MC
authors.lastname: Moe
authors.forename: Attila
authors.initials: A
authors.lastname: Vajas
authors.forename: László
authors.initials: L
authors.lastname: Fésüs
authors.forename: András
authors.initials: A
authors.lastname: Berta
authors.forename: Andrea
authors.initials: A
authors.lastname: Facskó
mesh_terms: D017304:Annexin A5 / Q000494:pharmacology; D023102:Anoikis / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005434:Flow Cytometry; D006801:Humans; D008264:Macrophages / Q000502:physiology*; D008268:Macular Degeneration / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D010718:Phosphatidylserines / Q000037:antagonists & inhibitors / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors; D014221:Triamcinolone / Q000494:pharmacology
chemical_list: D017304:Annexin A5; D010718:Phosphatidylserines; D014221:Triamcinolone