Researchers say they have found a link between a blinding eye disease called glaucoma and Alzheimer's disease. Investigators say the connection has to do with a protein called beta amyloid. VOA's Jessica Berman reports.
Scientists say the overproduction of beta amyloid, the brain protein that is responsible for the destruction of brain cells in Alzheimer's disease, is also responsible for glaucoma. They say optic nerves accumulate the same beta amyloid protein that is the underlying cause of neuron death in the brains of Alzheimer's patients.
Alzheimer's causes dementia and eventual death. Studies show glaucoma causes blindness in some 65 million people worldwide.
London University College ophthalmologist Francesca Cordeiro led a study of the link between the two diseases. She says researchers have found that the protein deposits seem to cause both diseases because Alzheimer's affects the brain and the optic nerves are directly connected to the brain.
She says investigators zeroed-in on the beta amyloid connection in experiments with mice.
"And in the model in fact that we used of glaucoma what we actual did is raise the pressure of the eye of these animals and show[ed] that beta amyloid was deposited in the retina and also cause[d] ... nerve cell death," she said.
The results of the study are published in Proceedings of the National Academy of Sciences.
Most exciting to investigators, according to Dr. Cordeiro, is they were able to halt the progression of glaucoma by using experimental drugs that stopped the deposits of beta amyloid.
"Furthermore, we showed that if we used three different drugs that actually changed or targeted different parts of the pathways for the beta amyloid being produced, we had a much greater effect than if we just used the drugs by themselves," she said. "That, as a strategy, has not been used in Alzheimer's disease before."
Dr. Cordeiro says one of the drugs used in the experiments is also being tested in an advanced clinical trial for Alzheimer's disease.
She says small studies show that up to two percent of the general population is affected by glaucoma. But she says it appears to affect more than 25 percent of people with Alzheimer's disease.
Dr. Cordeiro says researchers will now focus on whether people with glaucoma are at increased risk for developing Alzheimer's disease.