At 25 hertz, a carefully tuned magnetic field helped tiny cargo-carrying structures move again inside lab-grown nerve cells from people with ALS. The cells were not cured, and no one has tested this method as a treatment in people. But the Dresden study offers a new clue about how the disease might one day be approached.
ALS, or amyotrophic lateral sclerosis, damages motor neurons: the nerve cells that carry signals from the brain and spinal cord to muscles. As those signals fade, muscles weaken and waste away. The disease can first affect the arms or legs, or cause trouble speaking or swallowing. Existing treatments can extend life only modestly, so researchers are looking for other ways to protect nerve cells.
The study, published in the journal Cells, was led by cell biologist Dr. Arun Pal at the Helmholtz-Zentrum Dresden-Rossendorf, known as HZDR, with partners in Dresden and Rostock. The team studied motor neurons grown from stem cells made using cells from people with inherited forms of ALS. These neurons carried disease-causing changes in the FUS gene, which has a role in repairing DNA.
Researchers focused on mitochondria, which help supply cells with energy, and lysosomes, which break down waste. Both need to travel along axons, the long extensions that connect a nerve cell to other cells. In ALS cells, that transport was impaired. Using a powerful microscope and special chambers that separated cell bodies from axons, the team watched the structures move in living cells.
The researchers applied electromagnetic fields at different frequencies, strengths and orientations. A frequency of 25 hertz worked particularly well: transport of mitochondria and lysosomes along the axons sped up markedly. The effect lasted for about eight days after the last stimulation session, then gradually faded. One treatment did not produce an immediate effect; benefits appeared after four sessions.
The fields did not seem to repair the transport machinery directly. Instead, the findings point to a slower change in how the cells function. The team found that activity across thousands of genes shifted after stimulation, and processes involved in repairing DNA damage were reactivated. The source material describes the treated cells’ gene activity as changing substantially, but does not provide the full details of that analysis.
That indirect action may matter for future research. If a lasting response can be confirmed, treatment might not need to be continuous, Pal said. For now, however, the work is an early laboratory result in cultured human cells, not evidence that magnetic stimulation is safe or effective for people with ALS. The next challenge is to understand which gene changes drive the improved transport and whether the effect can be reproduced beyond the dish. The study gives researchers a specific setting to investigate: repeated stimulation, a 25-hertz frequency and a benefit that remained visible for days.