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On the origin of proteins in human drusen: The meet, greet and stick hypothesis. Prog Retin Eye Res 2018; 70:55-84. [PMID: 30572124 DOI: 10.1016/j.preteyeres.2018.12.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
Abstract
Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.
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Arya S, Emri E, Synowsky SA, Shirran SL, Barzegar-Befroei N, Peto T, Botting CH, Lengyel I, Stewart AJ. Quantitative analysis of hydroxyapatite-binding plasma proteins in genotyped individuals with late-stage age-related macular degeneration. Exp Eye Res 2018; 172:21-29. [DOI: 10.1016/j.exer.2018.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/16/2018] [Accepted: 03/22/2018] [Indexed: 12/17/2022]
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Ugarte M, Geraki K, Jeffery G. Iron accumulates in the primate choroid of the eye with aging as revealed with synchrotron X-ray fluorescence microscopy. Metallomics 2017; 8:1071-1080. [PMID: 27504972 DOI: 10.1039/c6mt00125d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Aging leads to an increase in iron-loaded cellular structures in the choroid of the eye. This study was carried out to determine the distribution and content of iron, zinc and copper in the macular retina, choroid and retrobulbar optic nerve of young (4-5 years, n = 3) and aged (15-16 years, n = 5) male non-human primates, Macaca fascicularis, whose ocular anatomy is similar to humans. Thirty μm-thick tissue sections were analysed with synchrotron X-ray fluorescence and stained histologically for iron deposition. Quantitative measurements showed high levels of iron, zinc and copper in the choroid and retinal pigment epithelium in the macular area and arachnoid layer in the retrobulbar optic nerve. In aged animals compared to young ones, there was an increase in iron in the choroid with larger deposits and iron-loaded cellular structures. Iron-accumulation within these cellular structures may contribute to choroidal function impairment in aging and age-related macular degeneration.
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Affiliation(s)
- Marta Ugarte
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK. and NIHR Biomedical Research Centre, Moorfields Eye hospital and UCL Institute of Ophthalmology, London, UK
| | - Kalotina Geraki
- I18, Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot, Oxfordshire OX11 0DE, UK
| | - Glen Jeffery
- UCL Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK
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Nishiguchi KM, Yokoyama Y, Fujii Y, Fujita K, Tomiyama Y, Kawasaki R, Furukawa T, Ono F, Shimozawa N, Togo M, Suzuki M, Nakazawa T. Analysis of Macular Drusen and Blood Test Results in 945 Macaca fascicularis. PLoS One 2016; 11:e0164899. [PMID: 27776188 PMCID: PMC5077098 DOI: 10.1371/journal.pone.0164899] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 10/03/2016] [Indexed: 01/07/2023] Open
Abstract
Age-dependent formation of macular drusen caused by the focal accumulation of extracellular deposits beneath the retinal pigment epithelium precede the development of age-related macular degeneration (AMD), one of the leading causes of blindness worldwide. It is established that inflammation contributes to the pathogenesis of drusen and AMD. However, development of a preemptive therapeutic strategy targeting macular drusen and AMD has been impeded by the lack of relevant animal models because most laboratory animals lack macula, an anatomic feature present only in humans and a subset of monkeys. Reportedly, macular drusen and macular degeneration develop in monkeys in an age-dependent manner. In this study, we analyzed blood test results from 945 Macaca fascicularis, 317 with and 628 without drusen. First, a trend test for drusen frequency (the Cochran–Armitage test) was applied to the quartile data for each parameter. We selected variables with an increasing or decreasing trend with higher quartiles at P < 0.05, to which multivariate logistic regression analysis was applied. This revealed a positive association of age (odds ratio [OR]: 1.10 per year, 95% confidence interval [CI]: 1.07–1.12) and white blood cell count (OR: 1.01 per 1 × 103/μl, 95% CI: 1.00–1.01) with drusen. When the monkeys were divided by age, the association between drusen and white blood cell count was only evident in younger monkeys (OR: 1.01 per 1 × 103/μl, 95% CI: 1.00–1.02). In conclusion, age and white blood cell count may be associated with drusen development in M. fascicularis. Systemic inflammation may contribute to drusen formation in monkeys.
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Affiliation(s)
- Koji M. Nishiguchi
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
- * E-mail:
| | - Yu Yokoyama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yusuke Fujii
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kosuke Fujita
- Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yusuke Tomiyama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryo Kawasaki
- Department of Public Health, Yamagata University Graduate School of Medical Science, Yamagata, Japan
| | - Toshinori Furukawa
- Kurashiki University of Science and the Arts, Department of Comparative Animal Science, Kurashiki, Japan
| | - Fumiko Ono
- Chiba Institute of Science, Faculties of Risk and Crisis Management, Choshi, Japan
| | - Nobuhiro Shimozawa
- Tsukuba Primate Research Center, National Institute of Biomedical Innovation, Health and Nutrition, Tsukuba, Japan
| | - Mutsumi Togo
- The Corporation for Production and Research of Laboratory Primates, Tsukuba, Japan
| | - Michihiro Suzuki
- The Corporation for Production and Research of Laboratory Primates, Tsukuba, Japan
| | - Toru Nakazawa
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan
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