Updated on 23 August 2013
Accumulation of iron in the hippocampus leads to destruction of myelin in the neurons and eventually to Alzheimer's disease
Singapore: A new reseach conducted by Dr George Bartzokis, professor of psychiatry, and his colleagues at the Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles (UCLA) revealed that accumulation of iron can lead to development of Alzheimer's disease. The research, which was co-authored by Dr Erika Raven, Dr Po Lu, Dr Todd Tishler and Dr Panthea Heydari and funded by the National Institutes of Health (NIH) and RCS Alzheimer's Foundation, will be published in the August edition of the Journal of Alzheimer's Disease.
The team compared the hippocampus, which is known to be damaged early in the disease, and the thalamus, an area that is generally not affected until the late stages, using sophisticated brain-imaging techniques. The study found that iron is increased in the hippocampus and is associated with tissue damage in that area. However, increased iron was not found in the thalamus.
Dr Bartzokis said that he destruction of myelin hinders communication between neurons and promotes the buildup of the plaques. These amyloid plaques in turn destroy more and more myelin, disrupting brain signaling and leading to cell death and the classic clinical signs of Alzheimer's.
Myelin is produced by cells called oligodendrocytes. These cells, along with myelin, have the highest levels of iron of any cells in the brain. Dr Bartzokis said that circumstantial evidence has long supported the possibility that brain iron levels might be a risk factor for age-related diseases like Alzheimer's. Although iron is essential for cell function, too much of it can promote oxidative damage, to which the brain is especially vulnerable.
Dr Bartzokis said, "It is difficult to measure iron in tissue when it is already damaged. But the MRI technology we used in this study allowed us to determine that the increase in iron is occurring together with the tissue damage. We found that the amount of iron is increased in the hippocampus and is associated with tissue damage in patients with Alzheimer's but not in the healthy older individuals or in the thalamus. So the results suggest that iron accumulation may indeed contribute to the cause of Alzheimer's disease. The accumulation of iron in the brain may be influenced by modifying environmental factors, such as how much red meat and iron dietary supplements we consume and, in women, having hysterectomies before menopause."