Light-induced deposits in Bruch's membrane of protoporphyric mice

J. D. Gottsch, L. A. Bynoe, J. B. Harlan, E. V. Rencs and W. R. Green
Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Md 21205.

Photosensitization of choriocapillary endothelium with blood-borne photosensitizers, such as protoporphyrin IX, has been proposed as a mechanism for the choriocapillary sclerosis and Bruch's membrane deposits seen in age-related macular degeneration. Utilizing a mouse model of protoporphyria with approximately a 10-fold increase in protoporphyrin IX level and exposure to blue light (14 microW/cm2; bandwidth, 390 to 430 nm), a time- and light-dependent increase in choriocapillary and sub-retinal pigment epithelium basal laminar-like deposits could be demonstrated at 7 months by transmission electron microscopy. Thickening of the choriocapillary endothelial basement membrane with a homogeneous electron-dense material was first noted in protoporphyric mice exposed to blue light for 13 weeks. At 28 weeks the experimental animals exhibited a thick band of homogeneous deposits at the level of the choriocapillary basement membrane and electron-dense fibrillogranular deposits of varying sizes along the inner aspect of Bruch's membrane, with fibrils measuring up to 16 nm, with a periodicity of 13 nm. These deposits contributed to an overall thickening of Bruch's membrane with narrowing of the choriocapillaris. The morphologic appearance and localization of these deposits within Bruch's membrane of this animal model are similar to previously described deposits noted in the aging Bruch's membrane prior to the development of age-related macular degeneration.

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Macular Pigment: A Review of Current Knowledge
Whitehead et al.
Arch Ophthalmol 2006;124:1038-1045.
ABSTRACT | FULL TEXT  

Cigarette Smoke-Related Oxidants and the Development of Sub-RPE Deposits in an Experimental Animal Model of Dry AMD
Espinosa-Heidmann et al.
IOVS 2006;47:729-737.
ABSTRACT | FULL TEXT  

Physiological role of collagen XVIII and endostatin
Marneros and Olsen
FASEB J. 2005;19:716-728.
ABSTRACT | FULL TEXT  

Ultrastructural Aging of the RPE-Bruch's Membrane-Choriocapillaris Complex in the D-Galactose-Treated Mouse
Ida et al.
IOVS 2004;45:2348-2354.
ABSTRACT | FULL TEXT  

Basal Laminar Deposit Formation in APO B100 Transgenic Mice: Complex Interactions between Dietary Fat, Blue Light, and Vitamin E
Espinosa-Heidmann et al.
IOVS 2004;45:260-266.
ABSTRACT | FULL TEXT  

Age-related changes in the transcriptional profile of mouse RPE/choroid
Ida et al.
Physiol. Genomics 2003;15:258-262.
ABSTRACT | FULL TEXT  

Molecular genetics of age-related macular degeneration
Stone et al.
Hum Mol Genet 2001;10:2285-2292.
ABSTRACT | FULL TEXT  

TIMP-3 in Bruch’s Membrane: Changes during Aging and in Age-Related Macular Degeneration
Kamei and Hollyfield
IOVS 1999;40:2367-2375.
ABSTRACT | FULL TEXT  

Basal Linear Deposit and Large Drusen Are Specific for Early Age-Related Maculopathy
Curcio and Millican
Arch Ophthalmol 1999;117:329-339.
ABSTRACT | FULL TEXT