Iron Implicated in Alzheimer’s Disease

Most researchers believe that Alzheimer’s Disease is caused by one of two proteins, namely – tau and beta-amyloid. As we age, it is thought that these proteins either disrupt signaling between neurons or simply kill them.  George Bartzokis, from the University of California/Los Angeles (UCLA; California, USA), and colleagues suggest a third possible cause: iron accumulation.  These researchers suspect that the destruction of myelin, the fatty tissue that coats nerve fibers in the brain, disrupts 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. To elucidate this process, the team used an MRI technique that can measure the amount of brain iron in ferritin, a protein that stores iron, in 31 patients with Alzheimer's and 68 healthy control subjects.  They tested their hypothesis that elevated tissue iron caused the tissue breakdown associated with Alzheimer's disease. They targeted the vulnerable hippocampus, a key area of the brain involved in the formation of memories, and compared it to the thalamus, which is relatively spared by Alzheimer's until the very late stages of disease.  The investigators found that iron is increased in the hippocampus and is associated with tissue damage in that area. But increased iron was not found in the thalamus.  The study authors submit that: “The data shows that in [Alzheimer’s Disease], [hippocampal] damage occurs in conjunction with ferritin iron accumulation.”