Cited by 396Retinal Diseases and TreatmentsRetinal Development and DisordersRetinoids in leukemia and cellular processes

The bisretinoids of retinal pigment epithelium

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Sparrow, Janet R., Gregory-Roberts, Emily, Yamamoto, Kazunori, Blonska, Anna, Ghosh, Shanti Kaligotla, Ueda, Keiko, Zhou, Jilin·2012·Progress in Retinal and Eye Research

Abstract

The retina exhibits an inherent autofluorescence that is imaged ophthalmoscopically as fundus autofluorescence. In clinical settings, fundus autofluorescence examination aids in the diagnosis and follow-up of many retinal disorders. Fundus autofluorescence originates from the complex mixture of bisretinoid fluorophores that are amassed by retinal pigment epithelial (RPE) cells as lipofuscin. Unlike the lipofuscin found in other cell-types, this material does not form as a result of oxidative stress. Rather, the formation is attributable to non-enzymatic reactions of vitamin A aldehyde in photoreceptor cells; transfer to RPE occurs upon phagocytosis of photoreceptor outer segments. These fluorescent pigments accumulate even in healthy photoreceptor cells and are generated as a consequence of the light capturing function of the cells. Nevertheless, the formation of this material is accelerated in some retinal disorders including recessive Stargardt disease and ELOVL4-related retinal degeneration. As such, these bisretinoid side-products are implicated in the disease processes that threaten vision. In this article, we review our current understanding of the composition of RPE lipofuscin, the structural characteristics of the various bisretinoids, their related spectroscopic features and the biosynthetic pathways by which they form. We will revisit factors known to influence the extent of the accumulation and therapeutic strategies being used to limit bisretinoid formation. Given their origin from vitamin A aldehyde, an isomer of the visual pigment chromophore, it is not surprising that the bisretinoids of retina are light sensitive molecules. Accordingly, we will discuss recent findings that implicate the photodegradation of bisretinoid in the etiology of age-related macular degeneration.

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Crossref · 10.1016/j.preteyeres.2011.12.001

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135 of 135 references verified0 citation errors · 0 not checkable

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  • Dysfunction of phagocytosis, lysosomal degradation, and waste removal by the RPE can lead to severe retinopathies, including age-related macular degeneration.

    “Dysfunction of such processes as phagocytosis, lysosomal degradation, and removal of waste products by the RPE can lead to severe retinopathies, including age-related macular degeneration (AMD).”

    From Chemistry of the Retinoid (Visual) Cycle (2014) · cites this paper as [270]

    Section 7.7 links RPE bisretinoid lipofuscin photooxidation to processes that may predispose the macula to AMD. But section 1 does not identify failed phagocytosis, lysosomal degradation, or waste removal as causes of retinopathy; it specifically argues against inhibited lysosomal enzymes as the explanation for lipofuscin accumulation. The claimed causal chain is therefore broader than the paper supports. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • A2E cannot be further metabolized and RPE cells are postmitotic, so A2E and related bisretinoids accumulate in the RPE in the form of lipofuscin deposits.

    “As A2E can not be further metabolized and as RPE cells are postmitotic, A2E and related bisretinoids accumulate in the RPE in the form of lipofuscin deposits.”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [74]

    Section 1 (page unavailable) says RPE lipofuscin accumulates with age and suggests that lysosomal enzymes do not recognize bisretinoid structures; Section 2.1 identifies A2E as a lipofuscin constituent. The paper does not establish postmitotic RPE cells as the reason for accumulation, and its Section 5 account of A2E photodegradation does not support the absolute claim that A2E cannot be further metabolized. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Although abundant lipofuscin accumulation is involved in the aetiology of certain retinal diseases such as AMD, Best disease and ABCA4-retinopathy, it also accumulates at a lower level with age in the RPE of healthy eyes.

    “Although abundant lipofuscin accumulation is involved in the aetiology of certain retinal diseases (e.g., AMD, Best disease and ABCA4-retinopathy), it accumulates at a lower level also with age in the RPE of healthy eyes [9,72,73,74,75].”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [74]

    Section 1 says RPE lipofuscin accumulates with age in healthy and diseased eyes, and section 7.1 identifies excessive accumulation in ABCA4-related disease. Section 7.7 proposes a possible contribution of lipofuscin products to AMD, but does not establish abundant accumulation as a cause of AMD; the retrieved passages do not address Best disease. Page numbers are unavailable in our copy. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • Lipofuscin compromises the function and viability of RPE cells and ultimately results in photoreceptor degeneration and a loss of vision.

    “Lipofuscin is an autofluorescent cellular waste product that compromises the function and viability of RPE cells and ultimately results in photoreceptor degeneration and a loss of vision [54,69,73,74,75].”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [74]

    Section 5 (page unavailable in our copy) reports that light exposure of A2E-containing RPE cells can cause cell damage and death. Section 8 links lipofuscin accumulation to RPE atrophy and photoreceptor degeneration, but specifically as a generally accepted explanation in juvenile-onset recessive Stargardt disease. The citing sentence presents this as an inevitable effect of lipofuscin generally; the source does not establish that broader claim or the stated progression to vision loss. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • In the membranes of outer photoreceptor segments, nonenzymatically formed toxic bisretinoids are converted upon phagocytosis in the acidic environment of RPE phagolysosomes to bisretinoid pyridinium compound A2E and related bisretinoids.

    “In the membranes of outer photoreceptor segments are nonenzymatically formed toxic bisretinoids. Upon phagocytosis, these bisretinoids are in the acidic environment of RPE phagolysosomes converted to bisretinoid pyridinium compound A2E and related bisretinoids [54,69,70,71,72,73,74].”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [74]

    Section 3.2 (page unavailable) reports nonenzymatic steps in bisretinoid formation and identifies A2PE in photoreceptor outer segments as the immediate precursor of A2E. It says A2PE is cleaved by phospholipase D, with that activity present in RPE lysosomal fractions; it does not establish that an acidic phagolysosomal environment converts bisretinoids generally into A2E and related compounds. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

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Cites

Flagged first, then by citations

5 of the 140 references couldn’t be matched to a known paper.

Research works printed but not linked: 4

  1. Delori FC Keilhauer C Sparrow JR Staurenghi G Holz FG Schmitz-Valckenberg S Spaide RF Bird AC Origin of fundus autofluorescence Atlas of Fundus Autofluorescence Imaging 2007 Berlin Heidelberg Springer-Verlag 17 29
  2. Majji AB Cao J Chang KY Hayashi A Aggarwal S Grebe RR de Juan E Invest Ophthalmol Vis Sci 2000 52 3936 3942 11053297
  3. Michaelides M Lois N Forrester JV Fundus autofluorescence in cone and cone-rod dystrophies Fundus Autofluorescence 2009 Philadelphia Lippincott Williams and Wilkins 153 166
  4. Nomura Y Takeda T Okuma Y The Senescence-Accelerated Mouse (SAM): An Animal Model of Senescence 2004 Amsterdam, The Netherlands Elsevier B.V.

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Authors
Sparrow, J. R., Gregory-Roberts, E., Yamamoto, K., Blonska, A., Ghosh, S. K., Ueda, K., & Zhou, J.
Affiliations
  • Columbia University Irving Medical Center (US)
  • Columbia University (US)
Corresponding author
Sparrow, Janet R.
Venue
Progress in Retinal and Eye Research
Publisher
Elsevier BV
Published
2012-03
Volume
31
Issue
2
Pages
121-135
ISSN
1350-9462 (ISSN-L)
OpenAlex
W2019731198
Cited by
392
References
140
Citations by year
2026: 19 · 2025: 26 · 2024: 26 · 2023: 24 · 2022: 23 · 2021: 34 · 2020: 35 · 2019: 33 · 2018: 29 · 2017: 28 · 2016: 25 · 2015: 31 · 2014: 30 · 2013: 21 · 2012: 8
FWCI
3.23
Type
journal article
Language
en
Open access
Locations
  • Progress in Retinal and Eye Research (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Eye Institute (R01EY012951, EY 12951, P30EY019007)
Topics
  • Health Sciences › Medicine › Ophthalmology › Retinal Diseases and Treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinal Development and Disorders
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinoids in leukemia and cellular processes
Keywords
bisretinoids, retinal pigment epithelium, lipofuscin, fundus autofluorescence, vitamin A aldehyde, photoreceptor outer segment phagocytosis, Stargardt disease, age-related macular degeneration, photodegradation, retinal degeneration
MeSH terms
Animals, Cattle, Fluorescence, Humans, Lipofuscin, Macular Degeneration, Retinaldehyde, Retinoids, Spectrometry, Fluorescence, Molecular Structure, Mice, Rats, Retinal Pigment Epithelium

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