Frederik J G M van Kuijk1, Scott W McPherson1, Heidi Roehrich1. 1. Departments of Ophthalmology and Pediatrics, Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School (Dr. van Kuijk), Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School (Dr. McPherson) and Histology Core for Vision Research Department of Ophthalmology and Visual Neurosciences (Roehrich).
Abstract
PURPOSE: Understanding the apparent paradoxical role of zinc in the pathogenesis and prevention of age-related macular degeneration (AMD) has been limited by the lack of animal models for its detection in sub-retinal epithelial deposits (drusen), a definitive early hallmark of AMD. In-vitro studies using Zinpyr-1 showed drusen contained high levels of zinc, but the probe was not suitable for in-vivo studies. This study compares Zinpyr-1 to ZPP1, a new fluorescein-based probe for zinc, to assess the potential of ZPP1 for in-vivo detection of zinc in drusen. METHODS: Flat mounts of human sub-RPE tissue using the probes were analyzed by fluorescence and confocal microscopy. Flat mounts of sub-RPE tissue from mice deficient in superoxide dismutase isoform-1 (CuZn-SOD-KO) or isoform-2 (Mn-SOD-RPE-KO) were analyzed with sub-RPE deposits confirmed by histology. RESULTS: Drusen are detected in greater numbers and intensity with ZPP1 compared to Zinpyr-1. Using ZPP1, drusen was detected in a sample from a 46-year old human donor without ocular history, suggesting that ZPP1 might be sensitive enough to detect drusen at an early stage. With CuZn-SOD KO mice, ZPP1 detected sub-RPE deposits at 10 months of age, whereas Zinpyr-1 required 14 months. CONCLUSION: Detection of sub-RPE deposits by ZPP1 was greatly enhanced compared to Zinpyr-1. This enhanced sensitivity will allow for more insightful analysis of zinc in AMD using human specimens and mouse models. This could result in the development of a sensitive in-vivo probe to enhance research on the role zinc in drusen formation and the early clinical diagnosis of AMD.
PURPOSE: Understanding the apparent paradoxical role of zinc in the pathogenesis and prevention of age-related macular degeneration (AMD) has been limited by the lack of animal models for its detection in sub-retinal epithelial deposits (drusen), a definitive early hallmark of AMD. In-vitro studies using Zinpyr-1 showed drusen contained high levels of zinc, but the probe was not suitable for in-vivo studies. This study compares Zinpyr-1 to ZPP1, a new fluorescein-based probe for zinc, to assess the potential of ZPP1 for in-vivo detection of zinc in drusen. METHODS: Flat mounts of human sub-RPE tissue using the probes were analyzed by fluorescence and confocal microscopy. Flat mounts of sub-RPE tissue from mice deficient in superoxide dismutase isoform-1 (CuZn-SOD-KO) or isoform-2 (Mn-SOD-RPE-KO) were analyzed with sub-RPE deposits confirmed by histology. RESULTS: Drusen are detected in greater numbers and intensity with ZPP1 compared to Zinpyr-1. Using ZPP1, drusen was detected in a sample from a 46-year old humandonor without ocular history, suggesting that ZPP1 might be sensitive enough to detect drusen at an early stage. With CuZn-SOD KO mice, ZPP1 detected sub-RPE deposits at 10 months of age, whereas Zinpyr-1 required 14 months. CONCLUSION: Detection of sub-RPE deposits by ZPP1 was greatly enhanced compared to Zinpyr-1. This enhanced sensitivity will allow for more insightful analysis of zinc in AMD using human specimens and mouse models. This could result in the development of a sensitive in-vivo probe to enhance research on the role zinc in drusen formation and the early clinical diagnosis of AMD.
Authors: Jonathan L Haines; Michael A Hauser; Silke Schmidt; William K Scott; Lana M Olson; Paul Gallins; Kylee L Spencer; Shu Ying Kwan; Maher Noureddine; John R Gilbert; Nathalie Schnetz-Boutaud; Anita Agarwal; Eric A Postel; Margaret A Pericak-Vance Journal: Science Date: 2005-03-10 Impact factor: 47.728
Authors: Dzenita Smailhodzic; Freekje van Asten; Anna M Blom; Frida C Mohlin; Anneke I den Hollander; Johannes P H van de Ven; Ramon A C van Huet; Joannes M M Groenewoud; Yuan Tian; Tos T J M Berendschot; Yara T E Lechanteur; Sascha Fauser; Chris de Bruijn; Mohamed R Daha; Gert Jan van der Wilt; Carel B Hoyng; B Jeroen Klevering Journal: PLoS One Date: 2014-11-13 Impact factor: 3.240