Eyes and sense of smell could act as indicators of Alzheimer's
Examining patients eye cells and ability to smell may help detect Alzheimer's disease earlier on, research on mice suggests.
In the past it has been difficult to diagnose the disease as the symptoms do not appear until considerable neurological damage has occurred.
In Alzheimer's disease many neurons die leading to the destruction of cells in the eye and loss of smell. Now teams of scientists are developing ways to identify symptoms earlier and possibly even reverse some of the damage.
Eye cells affected by the condition undergo two types of death. One is named apoptosis, where cells ‘commits suicide', the other necrosis, where the cells ‘explode'.
In the early stages of Alzheimer's some eye cells will undergo apoptosis, however as the disease progresses, more cells go through necrosis.
Using mice, researchers were able to identify the eye cells dying and work out how they were dying by tagging them with a fluorescent protein. The proteins were different colours - green for apoptosis and red for necrosis. They saw many green cells in the back of eye earlier on in the disease compared to red ones. By identifying the dying cells, scientists were able to administer the Alzheimer's drug memantine to reverse the effects of apoptosis.
Other research on mice has shown that plaques form on the part of the brain devoted to smell, when the disease begins to develop. After the plaques form a loss of smell usually ensues. Scientists hope through conducting olfactory (smell) tests on patients, they could be able to identify Alzheimer's earlier.
Both these methods of testing will be inexpensive and efficient, say researchers although more studies are needed to support their findings further.