After collecting 100 samples of brain tissue from deceased people with multiple sclerosis, experts identified 12 patients who didn’t have the classical white matter demyelination that’s categorized by the disease.
It took the research team 14 years to collect the tissue samples.
The evidence was strong enough to propose a new subtype of multiple sclerosis, one that didn’t have classic lesions in the brain’s white matter but still had loss of nerve fibers.
“Loss of nerve fibers without demyelination suggests, maybe, different kinds of MS that we can’t detect using imaging and clinical evaluation,” Bruce Bebo, executive vice president of research at the National Multiple Sclerosis Society, told Healthline. “This is one of the reasons why the MS Society is investing in imaging technology to distinguish other types of MS and treat it better.”
This new subtype is called myelocortical MS (MCMS).
The 12 people who showed signs of MCMS had lesions in the spinal cord and in the cortex.
The researchers found that in MCMS, part of the neurons become swollen. On an MRI, they mimic typical MS lesions representative of white matter myelin loss.
Experts told Healthline the research could lead to new treatments and even help answer the question of whether MS is primarily an autoimmune or a neurodegenerative disease.
Reaction to the study
Healthline caught up with Bruce Trapp, PhD, chair of Cleveland Clinic’s Lerner Research Institute Department of Neurosciences, and his associate, Dr. Daniel Ontaneda, clinical director of the brain donation program at Cleveland Clinic’s Mellen Center for Treatment and Research in MS.
In addition to identifying a new subtype of MS, Trapp told Healthline that having people without brain white matter demyelination gives experts a platform to look at for neuronal degeneration.
Trapp also noted that these patients cannot be identified by their brain MRI from typical MS patients.
All of these clues, however, could result in better treatment.
“This novel research further elucidates what has been known for some time, i.e. that there are other processes in MS that result in nerve damage besides demyelination. This finding could provide impetus for new therapeutic strategies,” said Dr. Barbara Giesser, professor of clinical neurology at the David Geffen School of Medicine at the University of California Los Angeles (UCLA) and clinical director of the UCLA MS program.
The results provide, “significant implications as to how we think about the disease,” said Ontaneda, who personally reviewed each tissue sample.
He explained there was no striking difference in response to treatment for the people with MCMS versus those with MS.
“Some patients had access to former DMTs, steroids, interferons, and the majority went on to secondary progressive MS,” Ontaneda told Healthline.
What kind of disease is MS?
Bebo said this study raises questions around whether MS is primarily an autoimmune disease or primarily a neurodegenerative disease.
“Most research suggests autoimmune,” he explained, “but this research shows that it may start as a neurodegenerative disease and moves to an autoimmune disease.”
The immune system, which is known to play a role in MS, doesn’t seem to be a part of these myelinated axons. No T cells or B cells were present as in typical MS.
“These results have implications in the realm of clinical research and developing therapies for MS,” Ontaneda said.
If the study results are accurate, then about 1 in 10 patients could present with MCMS. This presence could affect the way a person responds to treatment.
It could also affect clinical trials across the board.
This information could help experts learn what’s driving disease activity as well as determine biomarkers or other measures to identify the condition.
“We can take tissue we already have and compare with advanced MRI analyses to create new measurement tools,” explained Ontaneda.
This could allow people currently living with MS to eventually be evaluated for MSMC.
“Dr. Pratt is one of the highly regarded neuropathologists in the world,” said Bebo. “This study highlights the need to study MS and the tissue damaged in the brain. We can’t understand it unless we are studying human brain tissue from people with MS.”
“The Cleveland Clinic is very special,” added Bebo. “It has a rapid autopsy program.”
The clinic services people within the Cleveland area by offering a brain tissue donor program. The clinic is able to pull information quickly from a deceased person’s brain.
There are several options to preserve one’s brain tissues to help future research.
The three tissue banks listed on the National MS Society’s website are the Human Brain and Spinal Fluid Resource Center, the Rocky Mountain MS Center Tissue Bank, and the Accelerated Cure Project MS Repository.