Alzheimer's affects survival of newborn neurons, study shows
New research from a Franco-American team of researchers has shown that while the brains of mice affected by Alzheimer's disease are able to produce new brain cells, the survival time of these cells is extremely short. The brains of Alzheimer sufferers have plaques containing insoluble forms of a molecule called amyloid-beta peptide. This peptide has neurotoxic properties, and causes the loss of neurons throughout the brain, but particularly in the parts of the brain responsible for learning and memory, namely the hippocampus. One of the commonest symptoms of the disease is the loss of short-term memory. Scientists recently discovered that the hippocampus produces new brain cells throughout our lives. In this piece of research, the researchers studied mice with Alzheimer's to see what happens to these new brain cells. They found that although production and short-term survival of newborn neurons in the hippocampus was unaffected by the peptide, the survival of these cells four weeks later was dramatically reduced in mice with many amyloid plaques, as would be found in a human with late stage Alzheimer's. The loss of neurons in the brains of Alzheimer patients can be detected even in the early stages of the disease, when symptoms such as cognitive decline are not yet apparent. The fact that the problem seems to be due to poor survival of brain cells suggests that strategies known to promote the survival of brain cells, such as environmental stimulation or physical exercise, could help to slow the cognitive decline which is characteristic of the disease. The next step for the researchers is to determine precisely what prevents these newborn neurons from developing into mature, fully functional neurons. Over 25 million people around the world suffer from Alzheimer's, and it is the leading cause of dementia in adults. The research, which was led by scientists at the French National Centre for Scientific Research (CNRS), is published in the Journal of Neuroscience.
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France, United States