Researchers at the University of California, San Diego (UCSD) School of Medicine and the University of Utah have developed a mouse model of Age-Related Macular Degeneration (AMD), the leading cause of blindness in people over age 55, and Stargardt Macular Degeneration (STGD), a form of the disease that affects children and young adults.
The mouse model*, which was reported in the March 4, 2005 online edition of the Proceedings of the National Academy of Sciences, "now permits the testing of potential therapies for the "dry" version of age-related AMD and STGD in an animal model," said the study's co-senior author David S. Williams, Ph.D., UCSD professor of pharmacology and neurosciences. Currently there is no known treatment or cure for the disorder.
AMD affects about 11 million Americans, with dry AMD accounting for about 90 percent of all AMD. STGD strikes about 30,000 children and young adults in the U.S. Macular degeneration is caused by the deterioration of the central portion of the retina, the inside back layer of the eye that records images and sends them via the optic nerve from the eye to the brain. The retina's central portion, known as the macula, is responsible for focusing central vision in the eye, and it controls the ability to read, drive a car, recognize faces or colors, and see objects in fine detail.
The UCSD-Utah scientists said that the AMD and STGD forms of macular degeneration are characterized by high levels of debris called lipofuscin that accumulates in the retinal pigment epithelium (RPE) and results in its degeneration together with photoreceptor cells. Vision loss follows.
Noting that scientists have recently linked mutations in a gene called ELOVL4 to AMD and STGD, the UCSD-Utah investigators developed mice with a mutant form of ELOVL4, which caused the mice to develop significant lipofuscin accumulation and photoreceptor and RPE death in a pattern closely resembling the human counterpart.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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