A role for vitamin A in the formation of ocular lipofuscin

Julie Wassell, Mike Boulton

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Background - Lipofuscin granules in the retinal pigment epithelium are lipid protein aggregates which are thought to represent the lifelong accumulation of the non-degradable end products from the phagocytosis of photoreceptor outer segments. Given the increasing evidence for a key role for vitamin A in the formation of ocular lipofuscin, the fluorophores generated by reacting vitamin A with lipid were assessed. Methods - Reaction mixtures consisting of vitamin A (retinol) or its aldehyde (retinal) and (a) isolated rod outer segments, (b) the lipid extract of rod outer segments, (c) protein, or (d) liposomes were incubated at either pH 4.5 or 7.0 for up to 42 days. The fluorescence characteristics and mobility of the chloroform soluble fluorophores generated were compared with those extracted from purified human lipofuscin. Finally, the effect of lysosomal degradation on fluorophores generated in the above mixtures was assessed. Results - Major spectral changes were observed when ROS or liposomes were incubated with retinal. These changes were pH dependent and did not occur if retinal was replaced with retinol. A number of the fluorophores generated exhibited similar fluorescence characteristics and chromatographic mobility to those of lipofuscin. Neither the presence of protein nor exposure to lysosomal enzymes had any effect on the spectral profile or fluorophore mobility of the fluorophores generated. Conclusions - These results suggest that some of the chloroform soluble fluorophores of lipofuscin are formed as a direct reaction product of retinal and lipid.

Original languageEnglish (US)
Pages (from-to)911-918
Number of pages8
JournalBritish Journal of Ophthalmology
Volume81
Issue number10
StatePublished - Oct 1997
Externally publishedYes

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Lipofuscin
Vitamin A
Aldehydes
Rod Cell Outer Segment
Lipids
Chloroform
Liposomes
Fluorescence
Phagocytosis
Proteins
Epithelium

ASJC Scopus subject areas

  • Ophthalmology

Cite this

A role for vitamin A in the formation of ocular lipofuscin. / Wassell, Julie; Boulton, Mike.

In: British Journal of Ophthalmology, Vol. 81, No. 10, 10.1997, p. 911-918.

Research output: Contribution to journalArticle

Wassell, J & Boulton, M 1997, 'A role for vitamin A in the formation of ocular lipofuscin', British Journal of Ophthalmology, vol. 81, no. 10, pp. 911-918.
Wassell, Julie ; Boulton, Mike. / A role for vitamin A in the formation of ocular lipofuscin. In: British Journal of Ophthalmology. 1997 ; Vol. 81, No. 10. pp. 911-918.
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