Good news may be on the way for sufferers of multiple sclerosis – a team of scientists from Illinois-based Northwestern University, the University of Sydney, and the Myelin Repair Foundation in California have succeeded in halting the effects of the disease in lab mice. It all comes down to using nanoparticles to trick the immune system.
When someone has MS, their immune system attacks the myelin membrane that serves as an insulator for the nerve cells in their brain, spinal cord and optic nerve. With that membrane compromised, the nerve cells can’t properly conduct electrical signals, resulting in limb numbness, paralysis or blindness. Some treatments attempt to address this situation by suppressing the entire immune system, although this leaves patients open to infections, and increases their risk of cancer.
The new treatment incorporates biodegradable nanoparticles made from a polymer called Poly(lactide-co-glycolide), “an easily produced and already FDA-approved substance.” They were developed by Lonnie Shea, a professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering and Applied Science.
In the mouse trials, myelin was attached to the nanoparticles, which were then injected into mice with a disease very similar to relapsing remitting multiple sclerosis. Once in the bloodstream, the nanoparticles made their way to the spleen, where the blood is filtered and dying blood cells are disposed of. There, they were engulfed by immune cells known as macrophages.
Ordinarily when this happens, the dying cell releases proteins, letting the immune system know that no response is required. In this case, the nanoparticles were interpreted as ordinary dying cells, and their accompanying myelin was thus viewed as something that didn’t require an immune response. This in turn caused the immune system to call off its attack on the animals’ existing myelin membranes, essentially telling the myelin-specific T cells (white blood cells that go after foreign bodies) to “stand down.”
In this way, only the part of the immune system that attacked the myelin membranes was suppressed – everything else was left intact. The mice had no relapses for up to 100 days, which the scientists say is the equivalent of several years for a human MS patient.
It is believed that the same sort of technology could be used to treat other immune system-related disorders such as Type 1 diabetes, food allergies, and asthma. The material attached to the nanoparticles would simply need to be changed accordingly.
The team is now looking towards beginning clinical trails on human MS patients. In a trial already underway, myelin is being introduced to test subjects by attaching it to their own white blood cells. While this approach also shows promise, it is said to be considerably more expensive and labor-intensive than using the nanoparticles.
A paper on the research was published this week in the journal Nature Biotechnology.
Sources: Northwestern University Feinberg School of Medicine, National Institute of Biomedical Imaging and Bioengineering