According to a new study at the University of California, Los Angeles, excess iron may be the catalyst that turns tau and beta-amyloid proteins in the brain toxic, thus starting the development of Alzheimer’s disease. Tau and beta-amyloid proteins are thought to be responsible for the characteristic plaques and tangles found in aging brains. However, autopsies on elderly people with no symptoms of Alzheimer’s disease often show these plaques and tangles. This knowledge spurred researchers to begin a study in order to discover what additional factor is needed to kick start the disease process.
Dr. George Bartzokis, a professor of psychiatry at UCLA, was the senior author of the study. He and his colleagues found that excess iron can cause the tau and beta-amyloid proteins to become toxic. They theorize that these toxic proteins then build up in the hippocampus region of the brain destroying tissue and disrupting signaling between brain neurons.
Thirty-one people with Alzheimer's and 68 healthy control subjects participated in the study that used MRI scans to examine the hippocampus and thalamus regions of their brains. The scans showed that in the hippocampus region, the interaction of iron with amyloid proteins resulted in the protein toxicity, while the thalamus showed no such increase in iron levels or signs of tissue damage.
Bartzokis was quoted on Al Jazeera America as saying "The accumulation of amyloid is like gasoline, while excess iron is the flame. An excess of iron is destructive because it is a pro-oxidant metal, meaning it converts free radicals into highly reactive ones."
Bartzokis explained that the reason our brains accumulate iron as we age has to do with myelin, an insulating layer that forms around nerves in the brain. Myelin requires a lot of iron and as we age, increasing amounts are deposited. When these deposits become excessive, free radical damage occurs, eventually making the environment in the brain toxic.
The findings of the UCLA study were published in the August issue of the Journal of Alzheimer's Disease.
Can antioxidants help protect against Alzheimer’s?
A recent study, published in the Journal of Biological Chemistry, which was led by Professor Nigel Hooper of the University's Faculty of Biological Sciences at Leeds, UK found that drugs based on natural antioxidants such as green tea and resveritrol (from grape skins) can help detoxify the damaging free radicals. "It's a misconception that Alzheimer's is a natural part of aging; it's a disease that we believe can ultimately be cured through finding new opportunities for drug targets like this,” he said. This study found that purified extracts from green tea and red wine (specifically, the resveratrol in the red grape skins) interrupted the pathway that may lead to Alzheimer’s disease.
According to Dr. Simon Ridley, Head of Research at Alzheimer's Research UK, which partly funded the Leeds study, "Understanding the causes of Alzheimer's is vital if we are to find a way of stopping the disease in its tracks. While these early-stage results [of this study] should not be a signal for people to stock up on green tea and red wine, they could provide an important new lead in the search for new and effective treatments."