Key proteins involved in Alzheimers disease are also implicated in glaucoma, say researchers from University College Londons Institute of Ophthalmology. These findings, reported last month in the Proceedings of the National Academy of Sciences of the USA, suggest that drugs that target these proteins when treating Alzheimers patients may be used to treat glaucoma.1

In recent years, researchers have found that amyloid-beta, the major constituent of senile plaques found in patients with Alzheimers disease, is also involved in the development of retinal ganglion cell (RGC) apoptosis in glaucoma.

Other studies have shown that patients with Alzheimers disease have RGC loss associated with glaucomatous changes, such as optic neuropathy and visual function impairment.

For this study, the researchers used a new technology known as Detection of Apoptosing Retinal Cells, which they say enables them to visualize nerve cell damage in the retina. Using an established model of glaucoma in rats, they examined how amyloid-beta expression is associated with RGC apoptosis (cell death), neurotoxicity of RGC cells in vivo, and the effectiveness of single- and combined-agent therapies at targeting amyloid-beta in reducing RGC apoptosis.

Results showed that amyloid-beta induces significant apoptosis of the RGCs and has a potent neurotoxic effect on the cells.

Weve seen for the first time that there is a clear link between what causes Alzheimers disease and one of the basic mechanisms behind glaucoma, says ophthalmologist Francesca Cordeiro from University College London, who led the study. However, this doesnt mean that everyone with Alzheimers will develop glaucoma or vice versa. Glaucoma has a number of risk factors.

By contrast, earlier this year researchers from Copenhagen, Denmark, found that patients with primary-angle glaucoma did not have an increased rate of subsequent Alzheimers disease compared with patients with the other diagnoses.2

Still, Dr. Cordeiro and her colleagues found that drugs designed to prevent the buildup of amyloid-beta protein in Alzheimers patients may possibly be used as neuroprotective agents in glaucoma patients. One drug, bapineuzumab, is in clinical trials. When combined with two other Alzheimers treatments, the effects on glaucoma were even stronger.

Other research by Dr. Cordeiro and colleagues suggests that the retina can provide a window into the brain, allowing doctors to diagnose Alzheimers disease by looking for evidence of nerve cell death.

Also, the eye might one day be used to test potential treatments for Alzheimers disease. Since we have shown that drugs for Alzheimers disease can tackle glaucoma, then potentially we could use damaged retina to screen Alzheimers drugs that target beta-amyloid buildup. Dr. Cordeiro says.

1. Guo L, Salt TE, Luong V, et al. Targeting amyloid-beta in glaucoma treatment. Proc Natl Acad Sci USA 2007 Aug 14;104(33):13444-9.

2. Kessing LV, Lopez AG, Andersen PK, Kessing SV. No increased risk of developing Alzheimer disease in patients with glaucoma. J Glaucoma 2007 Jan;16(1):47-51.