Stem cells derived from the central nervous system may hold promise as a potential therapy for people with multiple sclerosis, say doctors in Italy who conducted a study using the cells with mice.1
Stem Cell Therapy May Repair MS Damage
The physicians, in Milan, Italy, injected neural stem cells into mice who had been induced to develop a disease similar to MS known as experimental autoimmune encephalomyelitis (EAE). In explaining the similarities between the two diseases, Giuseppe Scotti, MD, stated: "The result in damaged tissue is very much the same. Since the stem cells try to repair the damaged tissue, the model is absolutely superimposable." Scotti is professor and chairman of Neuroradiology at the University and Scientific Institute San Raffaele in Milan, Italy and the study's senior author.
Scotti's team intravenously injected the stem cells into the mice with EAE. Then, using MRI scans, they were able to monitor the stem cells homing in on regions where myelin had been stripped away in the rodents' central nervous systems.
Reversing Myelin Damage
Myelin destruction is a central characteristic of multiple sclerosis. The disease is thought to culminate in an abnormal immune system attack. Rather than targeting invading foreign organisms as it's set up to do, it's thought the immune system launches an attack against myelin in the central nervous system. This is a fatty sheath that covers nerve cells, and helps them communicate with each other. When myelin is destroyed, nerve cells are left vulnerable and unable to take part in normal communication. The result is the symptoms manifested in people with MS, such as changes in cognitive function, difficulty walking, fatigue and spasticity.2
"Cell therapies are a promising true alternative in the treatment of previously untreatable central nervous system disorders, multiple sclerosis included," said study investigator Letterio Politi, MD, a clinical assistant in the department of Neuroradiology at Ospedale San Raffaele in Milan.
The scientists used iron particles to magnetically label neural stem cells in the mice. Iron particles interfere with a magnetic field, and thus can be easily detected using MRI.
For the study, they injected 6 mice with stem cells, and compared the outcome with an additional group of 6 mice that received no stem cell injection. In the mice that received the stem cell therapy, the team observed them homing in on lesions in brain regions of the mice just 1 day later. As the myelin was repaired, the symptoms in the mice improved, they reported. "All 6 EAE mice transplanted with labeled [neural stem cells] showed an almost complete recovery from the disease, while untreated EAE mice showed disease progression and important disability," they wrote.
"In this case, stem cells increase the number of glial cells, the cells that produce myelin. Myelin is then restored," said Scotti, who is also dean of the Medical School at the University Vita-Salute San Raffaele in Milan.
MRI Monitoring
The ability to monitor stem cell migration is essential if the treatment is going to be adapted to MS patients, the Italian investigators stressed. "The development of this MRI-based method to track labeled cells non-invasively represents a crucial step toward the application of this therapy to humans," explained Politi. But more studies must be done before clinical trials could begin.
"We know the potential therapeutic action of stem cells and have great hopes, but we do not yet know the possible side effects," said Scotti. "If and when stem cell therapy becomes available for humans, monitoring with MRI will become almost indispensable."
1. Letterio P, Pluchino S, Bacigaluppi M, Cadioli M, Martino G, Scotti G. In vivo MRI-based tracking of magnetically labeled, intravenously-injected adult neural stem cells in mice affected by MOG35-55-induced experimental autoimmune encephalomyelitis (EAE). 90th Scientific Assembly and Annual Meeting. 2004 Nov 28-Dec 3. Chicago, IL.
2. National Multiple Sclerosis Society. About MS: Symptoms. About MS: What Causes MS?
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
