Gold-plated nanoparticles could rebuild nerves damaged by multiple sclerosis, according to a Northwestern Medicine study recently published in Scientific Reports.
There is no current therapy for multiple sclerosis (MS) that helps repair nerve cells, so these findings point to a possible breakthrough, according to Stephen Miller, PhD, the Judy Gugenheim Research Professor of Microbiology-Immunology and senior author of the study.
“At first, I was a little skeptical that gold nanocrystals could repair myelin, but it actually worked,” said Miller, who is also a professor of Dermatology and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
MS is an autoimmune disease in which immune cells mistakenly attack myelin, a fatty sheath that surrounds and insulates nerve endings. When myelin or the nerves themselves are damaged in MS, nerve cell communications slows or stops, causing a variety of neurological symptoms.
Current FDA-approved therapies for MS are limited to immunosuppressive drugs, aimed at dampening the harmful immune system activity. However, these drugs are global immune system inhibitors, leading to significant side effects for patients, Miller said.
“People become more susceptible to opportunistic infections and have higher rates of cancer if you’re on these drugs long-term,” Miller said.
Miller’s laboratory has been investigating more specific drugs that only target the culprit immune cells, but even with promising targets, these drugs are only half of the equation. Patients with MS usually aren’t diagnosed until the disease has significantly progressed and they start to show symptoms – by the time treatment begins, substantial nerve damage has already occurred.
“If we can combine the antigen-specific immune therapy with a myelin repair drug, we could actually see recovery,” Miller said.
There are a variety of potential myelin repair drugs currently being investigated, but one interesting approach is gold-plated nanocrystals. Preliminary studies showed these nanoparticles help jump-start myelin production by stimulating oligodendrocytes — the cells that create and lay down myelin onto nerve fibers.
In the current study, Miller examined the effects of gold nanocrystals in mouse models of MS. The investigators administered the nanocrystals orally, and found they did indeed stimulate re-myelination of nerve endings. Further analysis revealed that these nanocrystals were absorbed by oligodendrocytes — boosting these cells’ metabolism — which likely allowed oligodendrocytes to create and deposit myelin at a higher rate.
“These nanocrystals actually ‘rev up’ oligodendrocytes, and they appear to produce more myelin,” Miller said.
The specifics of how these nanocrystals increase oligodendrocyte metabolism are still unknown, but this is promising subject for future study, as any effective therapy for MS will require a dual approach, according to Miller.
“I don’t think a myelin repair drug would work on its own,” Miller said. “It has to be combined with immunotherapeutic drugs.”
This study was funded by Clene Nanomedicine, which manufactures nanocrystals.