- In people living with MS, new and existing myelin-producing cells (oligodendrocytes) can contribute to myelin repair, but current therapies cannot enhance or sustain the natural repair process.
- A non-invasive method called low intensity repetitive transcranial magnetic stimulation (LI-rTMS) can boost the survival of new oligodendrocytes in laboratory models, but it is unclear whether it can promote myelin repair.
- Daily sessions of LI-rTMS were found to increase the amount of myelin produced by oligodendrocytes and enhance myelin repair in laboratory models of MS.
What is low intensity repetitive transcranial magnetic stimulation (LI-rTMS)?
LI-rTMS uses a rapidly changing magnetic field to generate small electrical pulses in the brain, stimulating certain areas. It is currently used to treat depression in people where anti-depressants have not been successful.
There have also been a small number of rTMS clinical trials in people with MS, and in these trials, people have reported a reduction in fatigue, muscle spasticity and improved memory. However, how it leads to these benefits is unknown.
Previously, Professor Kaylene Young and her team found that this method promotes the survival and maturation of oligodendrocytes in laboratory models, but it is unclear whether it can promote myelin repair.
What did the researchers do?
Published in Cellular and Molecular Life Sciences, MS Australia-supported researcher Professor Kaylene Young and her team, at the Menzies Institute for Medical Research, set out to investigate whether LI-rTMS could promote myelin repair in laboratory models of MS.
They did this by labelling new and mature oligodendrocytes in the brain of laboratory models of MS with a fluorescent tag to trace the fate of these cells.
Using advanced microscopy and cutting-edge techniques, the team captured how these cells interacted in the brain and investigated the exciting potential for LI-rTMS to boost myelin repair.
What did the researchers find?
Professor Young and her team found that LI-rTMS promoted the following three aspects in laboratory models of MS:
- It boosted the myelin repair capacity of new oligodendrocytes. However, it did not increase the number of new oligodendrocytes.
- It boosted the myelin repair capacity of mature oligodendrocytes in the brain. This was particularly the case for the corpus callosum, which acts as a communication pathway between the two halves (hemispheres) of the brain.
- It increased the length and thickness of each section of myelin produced. This suggests that myelin repair is more efficient. The researchers also found that more nerve fibres were covered in myelin in treated areas.
What is the significance of this?
This study revealed a significant finding – that LI-rTMS promotes myelin repair in laboratory models of MS by affecting the behaviour of new and mature oligodendrocytes. While this requires further investigation, it presents a promising treatment that could be used alongside other MS therapies. As we know, treatments that promote myelin repair are one of the greatest unmet needs, as they can restore nerve function and limit nerve damage.
This groundbreaking study will form part of the newly launched “CMLS Editors’ Choice Articles collection”, which recognises and highlights the very best recent publications in Cellular and Molecular Life Sciences (CMLS).”
LI-rTMS is currently in a clinical trial for myelin repair in MS. The TAURUS phase 1 clinical trial results were released a few months ago, and showed that LI-rTMS is safe and well tolerated by people living with MS. The high compliance also indicated that this procedure is feasible for people with MS to adhere to. This trial has now been moved into Phase 2, which will focus on the effectiveness of LI-rTMS in promoting myelin repair and improving several clinical measures including mobility, fatigue and magnetic resonance imaging metrics.
Professor Kaylene Young says, “Our laboratory experiments told us that LI-rTMS could push brain cells to replace lost myelin. The next step was to find out if it could do that in the brains of people with MS – so we asked people with MS to help us design the TAURUS clinical trial. We finished recruiting study participants and collecting MRI scans last month and are now analysing the trial data”.
We look forward to hearing the results of this study once it is completed.
