UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Characterization of Calcium Phosphate Spherical Particles in the Subretinal Pigment Epithelium-Basal Lamina Space in Aged Human Eyes

Pilgrim, Matthew G; Marouf, Salma; Fearn, Sarah; Csincsik, Lajos; Kortvely, Elod; Knowles, Jonathan C; Malek, Goldis; ... Lengyel, Imre; + view all (2021) Characterization of Calcium Phosphate Spherical Particles in the Subretinal Pigment Epithelium-Basal Lamina Space in Aged Human Eyes. Ophthalmology Science , 1 (3) , Article 100053. 10.1016/j.xops.2021.100053. Green open access

[thumbnail of Knowles_Characterization of Calcium Phosphate Spherical Particles in the Subretinal Pigment Epithelium-Basal Lamina Space in Aged Human Eyes_VoR.pdf]
Preview
PDF
Knowles_Characterization of Calcium Phosphate Spherical Particles in the Subretinal Pigment Epithelium-Basal Lamina Space in Aged Human Eyes_VoR.pdf - Published Version

Download (5MB) | Preview

Abstract

Purpose: Micrometer-sized spherules formed of hydroxyapatite or whitlockite were identified within extracellular deposits that accumulate in the space between the basal lamina (BL) of retinal pigment epithelium (RPE) and the inner collagenous layer of Bruch's membrane (sub-RPE-BL space). This investigation aimed to characterize the morphologic features, structure, and distribution of these spherules in aged human eyes with and without clinical indications of age-related macular degeneration (AMD). Design: Experimental study. Participants: Five human eyes with varying degrees of sub-RPE-BL deposits were obtained from the University College London Institute of Ophthalmology and Moorfield's Eye Hospital Tissue Repository or the Advancing Sight Network. Two eyes were reported as having clinical indications of AMD (age, 76-87 years), whereas 3 were considered healthy (age, 69-91 years). Methods: Cadaveric eyes with sub-RPE-BL deposits were embedded in paraffin wax and sectioned to a thickness of 4-10 μm. Spherules were identified and characterized using high-resolution scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy, and time-of-flight secondary ion mass spectroscopy. Main Outcome Measures: High-resolution scanning electron micrographs of spherules, the size-frequency distribution of spherules including average diameter, and the distribution of particles across the central-peripheral axis. Elemental maps and time-of-flight secondary ion mass spectra also were obtained. Results: The precipitation of spherules is ubiquitous across the central, mid-peripheral, and far-peripheral axis in aged human eyes. No significant difference was found in the frequency of spherules along this axis. However, statistical analysis indicated that spherules exhibited significantly different sizes in these regions. In-depth analysis revealed that spherules in the sub-RPE-BL space of eyes with clinical signs of AMD were significantly larger (median diameter, 1.64 μm) than those in healthy aged eyes (median diameter, 1.16 μm). Finally, spherules showed great variation in surface topography and internal structure. Conclusions: The precipitation of spherules in the sub-RPE-BL space is ubiquitous across the central-peripheral axis in aged human eyes. However, a marked difference exists in the size and frequency of spherules in eyes with clinical signs of AMD compared to those without, suggesting that the size and frequency of spherules may be associated with AMD.

Type: Article
Title: Characterization of Calcium Phosphate Spherical Particles in the Subretinal Pigment Epithelium-Basal Lamina Space in Aged Human Eyes
Location: Netherlands
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.xops.2021.100053
Publisher version: https://doi.org/10.1016/j.xops.2021.100053
Language: English
Additional information: ©2021 by the American Academy of Ophthalmology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Published by Elsevier Inc.
Keywords: AMD, age-related macular degeneration, BL, basal lamina, BrM, Bruch’s membrane, C, Calcium, Choroid, Drusen, EDX, Energy dispersive x-ray spectroscopy, Ectopic calcification, H, hydrogen, Mg, Magnesium, N, Nitrogen, Na, sodium, O, oxygen, P, phosphorus, RPE, retinal pigment epithelium, Retina, SEM, scanning electron microscopy, Spherical particle, Sub-retinal pigment epithelium-basal lamina deposit, Sub-retinal pigment epithelium-basal lamina space, Sub–retinal pigment epithelium, ToF-SIMs, time of flight-secondary ion mass spectrometry, sub-RPE–BL space, sub-retinal pigment epithelium-basal lamina space
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Eastman Dental Institute > Biomaterials and Tissue Eng
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Eastman Dental Institute
URI: https://discovery.ucl.ac.uk/id/eprint/10158436
Downloads since deposit
10Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item