A magnetic resonance imaging (MRI) study at UCLA opens new doors to assessing and potentially preventing brain iron accumulation associated with risk of developing degenerative brain diseases such as Alzheimer's, Parkinson's and Dementia With Lewy Bodies.
Posted as an early online publication of the peer-reviewed journal Neurobiology of Aging, this largest-ever study of brain iron demonstrates gender difference in brain iron levels for the first time. Until now, researchers had considered the brain blood barrier as protection against accumulating too much iron from the body. The finding suggests instead that age-related brain iron accumulation is a modifiable risk factor for degenerative brain diseases.
In addition, the study finds a nearly perfect correlation between iron levels in various brain regions of study participants measured using MRI and those reported by past post-mortem studies. The finding demonstrates the ability of MRI analysis to accurately measure iron levels in brain tissues of living patients.
Previous studies have shown that high accumulation of iron in brain tissue causes oxidative damage and formation of plaques found in age-related neurodegenerative disorders such as Alzheimer disease. In addition, past population studies show men develop such diseases about five years earlier than women but brain iron levels increase with age in both genders.
"If you can measure it and learn how to modify it, then you can fix it," said Dr. George Bartzokis, lead author and professor of neurology at the David Geffen School of Medicine at UCLA. "Alzheimer disease rates double every five years after age 60, so a modifiable risk factor assessed by non-invasive means may represent potential interventions that could halve the number of cases of AD in the United States."
The UCLA team measured iron stored in ferritin molecules in the brain tissues of living subjects with MRI by using the Field Dependent Relaxation Rate Increase (FDRI) method. Iron was measured in four subcortical tissues, three white matter regions and the hippocampus of 165 healthy adults, ages 19 to 82.
In addition to the nearly perfect correlation between published post-mortem brain iron levels and those measured by FDRI, the study found that men have significantly higher ferritin iron than women in two subcortical regions and all three white matter regions.
The team also found significant age-related increases in ferritin iron in the hippocampus and three of the four subcortical regions, and decreases in one white matter region.