The accumulation of iron in the outer layer of the brain can lead to mental deterioration in people with Alzheimer’s, scientists report.
MRI scans over 17 years have shown that people with Alzheimer’s have higher iron levels in some regions of the brain – including deep gray matter, temporal lobes and neo-cortex – than those of the same age without the disease.
Iron concentrations correlate with a key protein known as beta amyloid, which groups in and around brain cells and causes Alzheimer’s.
The results suggest that drugs that reduce the iron load on the brain, known as cheators, could play a potential role in the treatment of Alzheimer’s disease.
Blood iron is essential for the neurological function of the brain, but the chemical element needs to be strongly regulated to avoid adverse effects.
Brain maps of healthy control participants and participants with Alzheimer’s. Iron accumulation was associated with cognitive deterioration regardless of brain volume loss. (Alzheimer’s disease is associated with higher rates of brain tissue loss than normal aging.)
WHAT IS AN MRL?
Magnetic resonance imaging (MrI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body.
An MRI scanner is a large tube that contains powerful magnets. You lie inside the tube during the sweep.
An MRI can be used to examine almost any part of the body, including the brain and spinal cord, bones and joints, sinuses, heart and blood vessels and internal organs – such as the liver, uterus or prostate.
The results of an MRI can be used to help diagnose conditions, plan treatments and assess how effective the previous treatment has been.
“Our study provides support for the hypothesis of impaired iron homeostasis in Alzheimer’s disease and indicates that the use of iron ants in clinical trials may be a promising treatment target,” said co-author Professor Reinhold Schmidt of the Medical University of Graz in Austria.
“Magnetic resonance-based iron mapping can be used as a biomarker for predicting Alzheimer’s disease and as a tool to monitor treatment response in therapeutic studies.”
Alzheimer’s disease is a progressive type of dementia that impairs and eventually destroys memory and other brain functions.
There is no cure, although some treatments are thought to slow progression and medications can help alleviate some of the symptoms.
Psychological treatments, such as cognitive stimulation therapy, can also be offered to patients to support their memory, problem-solving skills and language skills, says the NHS.
Alzheimer’s disease is caused by abnormal accumulation of proteins in and around brain cells.
Previous research has associated abnormally high levels of iron in the brain with Alzheimer’s disease.
High iron levels were first reported in the brains of people with Alzheimer’s in 1953, according to the Alzheimer’s Society UK.
Iron is a predominant element in the human body and is necessary for large biochemical processes such as oxygen transport and DNA synthesis.
Abnormal iron accumulation has been reported in numerous neurodegenerative disorders, but it is unclear whether increased iron deposition contributes to the development of these diseases or is a side effect or by-product.
Previous studies have identified that iron accumulation correlates with beta amyloid – the protein that groups in the brains of people with Alzheimer’s.
‘Brain map’ of a study participant superimposed with cortical and subcortical segmentations
These clusters form “plaques” that collect between neurons, also known as nerve cells, and disrupt cell function.
Iron is an essential element for the production of red blood cells, which carry oxygen around the body.
Deficiency can cause anemia, which makes us feel tired and breathless.
But an excess of iron in the blood – known as hemochromatosis or iron overload – can result from too much iron being absorbed from the food we eat.
This can result in excess iron being stored in our organs, which can lead to arthritis, liver disease, diabetes and heart problems.
In the brain, iron has been linked to the development of “reactive oxygen species” (ROS).
They’re oxygen molecules that have been altered by a chemical reaction.
ROS is believed to be an early contributor to the mechanisms underlying the development of Alzheimer’s disease.
Associations have also been found between iron tangles and neurofibrillar – abnormal accumulations of a protein called tau that collect neurons inside.
These tangles block the neuron’s transport system, which impairs communication between neurons.
It is known that deep gray matter structures of Alzheimer’s patients contain higher concentrations of cerebral iron.
The gray matter of the brain is rich in neural cell bodies and plays an important role in the central nervous system.
But less is known about the neocortex, the deeply grooved outer layer of the brain that is involved with language, conscious thinking and other important functions.
The researchers therefore performed mri scans of 200 people – half of whom had Alzheimer’s.
Of the 100 participants with Alzheimer’s, 56 underwent subsequent neuropsychic tests and a follow-up brain MRI 17 months later, on average.
Magnetic resonance imaging allowed scientists to create a brain iron map, determining iron levels in parts of the brain.
These include the temporal lobes – located at the bottom of the brain and vital for communication – and the occipital lobes at the back of the head, which help with visual processing.
Schematic representation of magnetic resonance processing. Left: Cortical and subcortical segmentations. Right: corrected brain map for macroscopic field inhomogeneities, where median values were calculated for each region and then used for additional statistical analyses
“We found evidence of increased iron deposition in deep gray matter and total neo-cortex, and regionally in temporal and occipital lobes, in Alzheimer’s patients compared to healthy individuals of age,” Professor Schmidt said.
“These results are all in line with the view that high concentrations of iron significantly promote beta amyloid deposition and neurotoxicity in Alzheimer’s disease.”
Brain iron accumulation was associated with cognitive deterioration regardless of brain volume loss.
Alzheimer’s disease is associated with higher rates of brain tissue loss than normal aging.
The team also found changes in iron levels over time in the temporal lobes correlated with cognitive decline in individuals with Alzheimer’s.
Impaired iron stability for people with Alzheimer’s indicates that iron kerators in clinical trials can be a promising treatment.
Iron tion therapy involves giving patients drugs, most commonly deferrioxamine, to free them from iron in their urine.
The results were published in the journal Radiology.
HOW TO DETECT ALZHEIMER’S
Alzheimer’s disease is a progressive brain disorder that slowly destroys memory, thinking skills and the ability to perform simple tasks.
It is the cause of 60% to 70% of dementia cases.
Most people with Alzheimer’s are 65 years or older.
More than 5 million Americans have Alzheimer’s.
It is not known what causes Alzheimer’s. Those who have the APOE gene are more likely to develop late-onset Alzheimer’s.
Signs and symptoms:
- Difficulty remembering newly learned information
- Mood and behavior changes
- Suspicion about family, friends and professional caregivers
- More severe memory loss
- Difficulty speaking, swallowing and walking
Stages of Alzheimer’s:
- Mild Alzheimer’s (early stage) – A person may be able to function from independently, but is having memory lapses
- Moderate Alzheimer’s (mid-stage) – Usually the longer stage, the person can confuse words, get frustrated or irritated, or have sudden behavioral changes
- Severe Alzheimer’s disease (in the late stage) – In the final stage, individuals lose the ability to respond to their environment, continue a conversation and eventually control movement
There is no known cure for Alzheimer’s, but experts suggest physical exercise, social interaction and adding omega-3 fats to your diet to prevent or slow down the onset of symptoms.