Abstract

Melanosomes, lipofuscin, and melanolipofuscin are the three principal types of pigmented granules found in retinal pigment epithelium (RPE) cells. Changes in the density of melanosomes and lipofuscin in RPE cells are considered hallmarks of various retinal diseases, including Stargardt disease and age-related macular degeneration (AMD). Herein, we report the potential of an in vivo multimodal imaging technique based on directional back-scattering and short-wavelength fundus autofluorescence (SW-FAF) to study disease-related changes in the density of melanosomes and lipofuscin granules in RPE cells. Changes in the concentration of these granules in Abca4−/− mice (a model of Stargardt disease) relative to age-matched wild-type (WT) controls were investigated. Directional optical coherence tomography (dOCT) was used to assess melanosome density in vivo, whereas the autofluorescence (AF) images and emission spectra acquired with a spectrometer-integrated scanning laser ophthalmoscope (SLO) were used to characterize lipofuscin and melanolipofuscin granules in the same RPE region. Subcellular-resolution ex vivo imaging using confocal fluorescence microscopy and electron microscopy was performed on the same tissue region to visualize and quantify melanosomes, lipofuscin, and melanolipofuscin granules. Comparisons between in vivo and ex vivo results confirmed an increased concentration of lipofuscin granules and decreased concentration of melanosomes in the RPE of Abca4−/− mice, and provided an explanation for the differences in fluorescence and directionality of RPE scattering observed in vivo between the two mouse strains.

Details

Title
In vivo multimodal retinal imaging of disease-related pigmentary changes in retinal pigment epithelium
Author
Meleppat, Ratheesh K 1 ; Ronning, Kaitryn E 2 ; Karlen, Sarah J 3 ; Burns, Marie E 4 ; Pugh, Edward N, Jr 5 ; Zawadzki, Robert J 1 

 University of California Davis, UC Davis Eyepod Imaging Laboratory, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684); University of California Davis, Department of Cell Biology and Human Anatomy, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684); University of California Davis, Department of Ophthalmology and Vision Science, Sacramento, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684) 
 University of California Davis, Center for Neuroscience, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684) 
 University of California Davis, Department of Cell Biology and Human Anatomy, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684) 
 University of California Davis, Center for Neuroscience, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684); University of California Davis, Department of Ophthalmology and Vision Science, Sacramento, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684) 
 University of California Davis, UC Davis Eyepod Imaging Laboratory, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684); University of California Davis, Department of Cell Biology and Human Anatomy, Davis, USA (GRID:grid.27860.3b) (ISNI:0000 0004 1936 9684) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2559949984
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.