Multi-nucleate retinal pigment epithelium cells of the human macula exhibit a characteristic and highly specific distribution

Abstract Background: The human retinal pigment epithelium (RPE) is reportedly 3% bi-nucleated. The importance to human vision of multi-nucleated (MN)-RPE cells could be clarified with more data about their distribution in central retina. Methods: Nineteen human RPE-flatmounts (9 ≤ 51 years, 10 > 80 years) were imaged at 12 locations: 3 eccentricities (fovea, perifovea, near periphery) in 4 quadrants (superior, inferior, temporal, nasal). Image stacks of lipofuscin-attributable autofluorescence and phalloidin labeled F-actin cytoskeleton were obtained using a confocal fluorescence microscope. Nuclei were devoid of autofluorescence and were marked using morphometric software. Cell areas were approximated by Voronoi regions. Mean number of nuclei per cell among eccentricity/quadrant groups and by age were compared using Poisson and binominal regression models. Results: A total of 11,403 RPE cells at 200 locations were analyzed: 94.66% mono-, 5.31% bi-, 0.02% tri-nucleate, and 0.01% with 5 nuclei. Age had no effect on number of nuclei. There were significant regional differences: highest frequencies of MN-cells were found at the perifovea (9.9%) and near periphery (6.8%). The fovea lacked MN-cells almost entirely. The nasal quadrant had significantly more MN-cells compared to other quadrants, at all eccentricities. Conclusion: This study demonstrates MN-RPE cells in human macula. MN-cells may arise due to endoreplication, cell fusion, or incomplete cell division. The topography of MN-RPE cells follows the topography of photoreceptors; with near-absence at the fovea (cones only) and high frequency at perifovea (highest rod density). This distribution might reflect specific requirements of retinal metabolism or other mechanisms addressable in further studies.

[1]  Danielle B. Gutierrez,et al.  Quantitative autofluorescence and cell density maps of the human retinal pigment epithelium. , 2014, Investigative ophthalmology & visual science.

[2]  P. Rakic,et al.  Genesis of the retinal pigment epithelium in the macaque monkey , 1995, The Journal of comparative neurology.

[3]  David Williams.  Aliasing in human foveal vision , 1985, Vision Research.

[4]  R. Sidman,et al.  Growth and development of the mouse retinal pigment epithelium. I. Cell and tissue morphometrics and topography of mitotic activity. , 1987, Developmental biology.

[5]  A. Harman,et al.  Changing topography of the RPE resulting from experimentally induced rapid eye growth , 1997, Visual Neuroscience.

[6]  G. Jeffery,et al.  Mature retinal pigment epithelium cells are retained in the cell cycle and proliferate in vivo , 2008, Molecular vision.

[7]  L. Feeney.  Lipofuscin and melanin of human retinal pigment epithelium. Fluorescence, enzyme cytochemical, and ultrastructural studies. , 1978, Investigative ophthalmology & visual science.

[8]  G. Pavlath,et al.  Myoblast fusion: lessons from flies and mice , 2012, Development.

[9]  C. Chevalier,et al.  Endoreduplication in higher plants , 2000, Plant Molecular Biology.

[10]  A. Hendrickson,et al.  Human photoreceptor topography , 1990, The Journal of comparative neurology.

[11]  Adam M. Dubis,et al.  Adaptation of the central retina for high acuity vision: Cones, the fovea and the avascular zone , 2013, Progress in Retinal and Eye Research.

[12]  A. Maddox,et al.  Cytokinesis, ploidy and aneuploidy , 2012, The Journal of pathology.

[13]  C. Curcio,et al.  Lipoprotein particles of intraocular origin in human Bruch membrane: an unusual lipid profile. , 2009, Investigative ophthalmology & visual science.

[14]  Danielle B. Gutierrez,et al.  Lack of correlation between the spatial distribution of A2E and lipofuscin fluorescence in the human retinal pigment epithelium. , 2013, Investigative ophthalmology & visual science.

[15]  A. Maminishkis,et al.  Control of chemokine gradients by the retinal pigment epithelium. , 2008, Investigative ophthalmology & visual science.

[16]  Sina Farsiu,et al.  Anti-amyloid therapy protects against retinal pigmented epithelium damage and vision loss in a model of age-related macular degeneration , 2011, Proceedings of the National Academy of Sciences.

[17]  D. Pellman,et al.  From polyploidy to aneuploidy, genome instability and cancer , 2004, Nature Reviews Molecular Cell Biology.

[18]  M. Tso,et al.  The Retinal Pigment Epithelium: III. Growth and Development , 1968 .

[19]  E. Friedman,et al.  The retinal pigment epithelium. I. Comparative histology. , 1967 .

[20]  S. Teitelbaum,et al.  Genetic regulation of osteoclast development and function , 2003, Nature Reviews Genetics.

[21]  Christine A. Curcio,et al.  The spatial resolution capacity of human foveal retina , 1989, Vision Research.

[22]  G. Sakuta,et al.  Human hepatocyte polyploidization kinetics in the course of life cycle , 1993, Virchows Archiv. B, Cell pathology including molecular pathology.

[23]  A. Vignery,et al.  Osteoclasts and giant cells: macrophage–macrophage fusion mechanism , 2000, International journal of experimental pathology.

[24]  A. de Bruin,et al.  Physiological significance of polyploidization in mammalian cells. , 2013, Trends in cell biology.

[25]  Christopher S. Langlo,et al.  In vivo imaging of human cone photoreceptor inner segments. , 2014, Investigative ophthalmology & visual science.

[26]  R. Robb.  Regional changes in retinal pigment epithelial cell density during ocular development. , 1985, Investigative ophthalmology & visual science.

[27]  Glen Jeffery,et al.  Drusen are associated with local and distant disruptions to human retinal pigment epithelium cells. , 2009, Experimental eye research.

[28]  S. Celton-Morizur,et al.  The insulin/Akt pathway controls a specific cell division program that leads to generation of binucleated tetraploid liver cells in rodents. , 2009, The Journal of clinical investigation.

[29]  R. Bone,et al.  Light distributions on the retina: relevance to macular pigment photoprotection. , 2012, Acta biochimica Polonica.

[30]  Luca Comai,et al.  The advantages and disadvantages of being polyploid , 2005, Nature Reviews Genetics.

[31]  B. Fleischmann,et al.  Cardiomyocyte cell cycle control and growth estimation in vivo--an analysis based on cardiomyocyte nuclei. , 2010, Cardiovascular research.

[32]  R. T. Smith,et al.  Visualization of the optic fissure in short-wavelength autofluorescence images of the fundus. , 2012, Investigative ophthalmology & visual science.

[33]  Olaf Strauss,et al.  The retinal pigment epithelium in visual function. , 2005, Physiological reviews.

[34]  O. Pomerantzeff,et al.  Retinal illuminance using a wide-angle model of the eye. , 1988, Journal of the Optical Society of America. A, Optics and image science.

[35]  A. Kooijman,et al.  Light distribution on the retina of a wide-angle theoretical eye. , 1983, Journal of the Optical Society of America.

[36]  C. Kastner,et al.  The Generalised Estimating Equations: An Annotated Bibliography , 1998 .