Aerobic photoreactions of retinal pigment granules with aging

M. Rózanowska, M. E. Boulton, J. M. Burke, W. Korytowski, T. Sarna, M. Zarȩba

Research output: Contribution to journalArticle

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Abstract

Purpose. Aerobic photoexcitation of melanin leads to consumption of oxygen with stoichiometric formation of hydrogen peroxide. However, we have found recently that this product of oxygen reduction accounts for only a fraction of oxygen consumed by melanin granules from human RPE upon irradiation with blue light (Rozanowska et al., 1995). We measured selected products of aerobic photoreactions of melanin, melanolipofuscin and lipofuscin granules isolated from RPEs of human donors of different age, to determine whether aging modifies oxygen-dependent photochemistry of retinal pigment granules. Methods. Photoconsumption of oxygen and photoformation of hydrogen peroxide in aqueous suspension of pigment granules were measured electrochemically using specific electrodes. Lipid hydroperoxides were determined by iodometric method after chloroform-methanol extraction. Results. While the rate of oxygen photoconsumption was highest in lipofuscin and lowest in melanin granules, the corresponding yield of photoformation of hydrogen peroxide was found to be inversly related, i.e. it was significantly lower in lipofuscin than in melanin. We also found an increased photoformation of lipid hydroperoxides in pigment granules from aged human RPEs such as lipofuscin and melanolipofuscin. Conclusions. Lipofuscin and complex pigment granules that are apparent in aged human RPE, apper to be susceptible to photoinduced peroxidation of lipids and may generate potentially cytotoxic species.

Original languageEnglish (US)
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number3
StatePublished - Feb 15 1996
Externally publishedYes

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Lipofuscin
Retinal Pigments
Melanins
Oxygen
Hydrogen Peroxide
Lipid Peroxides
Photochemistry
Chloroform
Oxygen Consumption
Lipid Peroxidation
Methanol
Suspensions
Electrodes
Light

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Rózanowska, M., Boulton, M. E., Burke, J. M., Korytowski, W., Sarna, T., & Zarȩba, M. (1996). Aerobic photoreactions of retinal pigment granules with aging. Investigative Ophthalmology and Visual Science, 37(3).

Aerobic photoreactions of retinal pigment granules with aging. / Rózanowska, M.; Boulton, M. E.; Burke, J. M.; Korytowski, W.; Sarna, T.; Zarȩba, M.

In: Investigative Ophthalmology and Visual Science, Vol. 37, No. 3, 15.02.1996.

Research output: Contribution to journalArticle

Rózanowska, M, Boulton, ME, Burke, JM, Korytowski, W, Sarna, T & Zarȩba, M 1996, 'Aerobic photoreactions of retinal pigment granules with aging', Investigative Ophthalmology and Visual Science, vol. 37, no. 3.
Rózanowska M, Boulton ME, Burke JM, Korytowski W, Sarna T, Zarȩba M. Aerobic photoreactions of retinal pigment granules with aging. Investigative Ophthalmology and Visual Science. 1996 Feb 15;37(3).
Rózanowska, M. ; Boulton, M. E. ; Burke, J. M. ; Korytowski, W. ; Sarna, T. ; Zarȩba, M. / Aerobic photoreactions of retinal pigment granules with aging. In: Investigative Ophthalmology and Visual Science. 1996 ; Vol. 37, No. 3.
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