A new form of magnetic resonance imaging can reveal where so-called epigenetic changes have occurred in the brain. The technique, which requires a special diet, can image chemical labels added to DNA. Epigenetic MRI, or eMRI as the team call it, has only been tested on piglets so far, but should work in people, too.
鈥淲e expect eMRI to be readily translated to humans and thus enable many new investigations into the epigenetic basis of brain function, behavior, and disease,鈥� write and at the University of Illinois Urbana-Champaign and their colleagues.
Functional MRI has revealed much about the brain by detecting which parts are active at any one moment. It is now even possible to reconstruct what people are seeing from fMRI scans.
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Over a longer period, changes in the activity of genes are thought to play an important role in learning and memory. One of the ways gene activity can be changed is by adding labels to DNA that suppress gene activity, with so-called methyl groups being the most common label.
Until now, there has been no non-invasive way to study epigenetic changes in the brain. It requires brain dissection or genetically modifying animals. But eMRI simply involves eating a special diet in which all forms of the amino acid methionine 鈥� one of the building blocks of proteins 鈥� contain the carbon-13 isotope. Normally, only about 1 in 100 carbon atoms is carbon-13.
Methionine is the source of the methyl groups added to DNA. So, after being on the diet for a while 鈥� the piglets were fed a special milk with substituted amino acids for 10 or 32 days 鈥� all the newly added methyl groups in the brain will contain carbon-13, which is detectable by a form of MRI. Those fed for longer periods had more labels detected.
The carbon-13 is incorporated into other molecules too, but the team says methyl groups have distinctive properties that enable them to be distinguished.
The approach does have a lot of limitations. The resolution is low and it gives only a general picture of where new methyl labels have been added, not which genes are involved. Nevertheless, the team expects it to reveal much, such as how DNA methylation changes as we age and as a result of specific diseases.
快猫短视频 contacted the researchers, but they didn鈥檛 want to talk to the press prior to publication in a peer-reviewed journal.
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