Could replacing myelin in diseases like MS be as simple as stimulating individual axons?

New research from Monash University has found that stimulating nerve cells in the brain can result in the active development of myelin, the protective sheath that makes neurones work faster and which becomes depleted in diseases like multiple sclerosis (MS).

The study, published in Nature Communications, has for the first time revealed that triggering individual nerve cells in the brains of mice can lead to the myelination of their previously “naked” axons and that, importantly, the myelin surrounding these axons becomes thicker, meaning that the axons can transmit messages much faster and more efficiently.

According to lead researcher, Dr Tobias Merson from the Australian Regenerative Medicine Institute (ARMI) at Monash University, the results may explain why training for a particular skill such as juggling or practicing a musical instrument has been shown, in previous studies, to alter white matter circuits in the brain, as revealed by MRI. “Our study showed that stimulating individual nerve cells in the brain, as we did in our animal models, leads to the laying down of newly generated myelin around these nerve cells,” he said.

“By stimulating individual axons, we have been able to actively increase the level of myelination, which we know is directly related to improved motor task performance.”

The researchers, who are also from the Universities of Melbourne and Queensland and the Oregon Health and Science University in the United States, wanted to determine how myelination is controlled at the individual neuronal level in the mammalian brain. Using a gene that has no action in the mouse brain unless triggered by a particular drug, the researchers could stimulate individual axons and then determine what happened. They found that the stimulation of axons triggered the brain to produce new cells that would preferentially lay down myelin on the activated axons.

The study could mean that the activation of axons – either by something as benign as doing brain exercises or through an external stimulation such as via transcranial direct current stimulation (tDCS) – may lead to the remyelination of nerve cells in patients with diseases such as MS, Dr Merson said.

The research group is currently studying both these triggers – brain exercises and neuronal stimulation – to see whether they can lead to remyelination of nerve cells.

Dr Matthew Miles CEO, MS Research Australia said his organization is proud to be supporting the incredibly important work of Dr Merson. “There is a real need for more research into MS as we are getting so much closer to stopping and reversing the disease's effect, and Australian researchers like Dr Merson are at the forefront of research breakthroughs. With the increasing pressures on medical research funding in Australia, it is crucial that we are able to support our best and brightest to keep up the momentum in MS research.”