A group of scientists say they have made a surprising and potentially very important discovery in the brains of two people with Alzheimer’s disease: traces of a certain form of iron and copper deep in amyloid plaque deposits, a key marker of fatal disease. The discovery raises more questions about how Alzheimer’s disease develops and may one day point a new way to detect or treat the underlying dysfunction that causes it.
Iron and copper are elements that are found in small amounts throughout the body, including the brain. They can perform very important functions, such as being parts of enzymes vital to our healthy function. Both can come in different degrees of oxidation when they are part of a compound, which means they lose or gain electrons. Because some forms of these elements can be dangerous to us, causing chemical reactions that damage cells, the body usually does a good job of regulating which types of iron and copper should be present in our system at all times.
However, the regulation of these metals does not seem to work as well in the brains of people with Alzheimer’s disease. Those with the disorder develop deposits of improperly folded amyloid beta and tau, which are called plaques and entanglements, respectively. And there is some evidence suggested that toxic forms of iron and copper can be found inside these plaques.
To better understand this possible link, researchers from the United Kingdom, Germany and the United States are collaborating on a new study, published Wednesday in Scientific Progress. They used an X-ray image to analyze the specific chemical composition of the plaques taken from the brains of two deceased donors with severe Alzheimer’s disease. They then found elemental and metallic nanoparticles of iron and copper in the cores of these plates, meaning that the elements had no oxidation – missing or added electrons.
Although some types of bacteria, fungi and plants are known to produce these types of metals, this type of iron and copper was first documented in human tissue, according to the authors. And it can help explain how plaque damages the brain.
“The metallic forms of iron and copper we observe have significantly different chemical and magnetic properties than their less reactive oxide forms, in which iron and copper are stored primarily in the human body,” said senior author Neil Telling, a professor of biomedical nanophysics at Kiel. A university in the UK, told Gizmodo in an email. “The surfaces of metallic copper and iron are highly unstable and react easily with their surroundings, with the potential to cause damage to brain cells.”
Of course, potential findings such as this need to be further explored and validated by other researchers before they can be accepted as true. Even if this is a real find, there are many unanswered questions. It has not yet been confirmed, for example, whether these metals can only be found in the brains of Alzheimer’s patients. In addition, their exact origin is still a mystery, although past research by the Telling team and others has suggested that amyloid plaques can cause chemical reactions that can turn less reactive forms of these elements into something more dangerous. Some studies too to raise the ability of amyloid plaques to protect us from these toxic metals, Telling noted, so the link between all of these factors may be more complex than we think.
In any case, Telling and his team plan to continue digging into this. And if this area continues to show promise, it could very well lead to new directions in understanding Alzheimer’s disease and other neurological disorders associated with deceptive proteins, such as Parkinson’s disease.
“This line of research could eventually lead to new treatments targeting metals as well as amyloid proteins that are currently being considered,” he said. “The presence of small magnetic iron particles in the plaques can also help diagnose and monitor disease progression, as they can generally be detected by MRI scanners.”