Autoimmune disease affects up to 24 million Americans. The disease is characterized by one's immune system attacking non-foreign cells, often essential to life, ultimately leading to chronic health issues that cannot be treated indefinitely.

Multiple sclerosis is an autoimmune disease of the nervous system. Due to the condition, the immune system begins to attack myelin sheath cells and forces nerves to deteriorate. The myelin sheath cells are meant to surround the nerve cells in order to protect them from harm, as well as to ensure that their chemical and electrical signals get to their designated locations, instead of becoming intercepted. Multiple sclerosis thus causes a wide array of chronic issues, since the nervous system is connected in all body parts, most notably the brain and spinal cord.

For years, researchers have grappled with the notion of regenerating myelin. However, the cells that make the myelin, called oligodendrocytes, are not well-studied. In a new study using zebrafish, researchers have found that oligodendrocytes produce myelin for up to five hours before stopping. New oligodendrocytes are made throughout life until the age of 30.

When researchers applied an enzyme that allows oligodendrocytes to regulate the myelin they make, 21 percent more axons became myelinated. This is promising, as it is just an enzyme they added, instead of an entirely new cell. Addition of cells during potential treatment is risky, as the new cells can be rejected by the body and lead to widespread immune shock, or the cell may bypass control mechanisms and become cancerous. The efficacy of the enzyme to myelin or nerve cells indicates that it is just the enzyme that is lacking in multiple sclerosis patients, instead of entire cell groups.

Often, in multiple sclerosis patients, myelination persists until a certain age. At the point where symptoms become chronic, myelination has stopped. However, the oligodendrocytes cells, with the capacity to make more myelin, are still there. The researchers have found that it is a lack of enzymes, and not a lack of cells, that create the symptoms of multiple sclerosis.

Their finding regarding an oligodendrocytes' ability to make myelin for only five hours can be utilized in other studies. The five-hour work of oligodendrocytes appears to be a growth regulatory mechanism of the cells, as the myelin cells can still be retracted after this five-hour period. Researchers could potentially manipulate this growth regulation and increase myelin production times of oligodendrocytes in multiple sclerosis patients to alleviate some of their symptoms.

Treatments could focus on either finding — providing the enzymes that create more myelin, or getting oligodendrocytes to produce myelin for longer than their five-hour time frame. Currently, there is no cure for multiple sclerosis; the drugs that exist for its treatment are used to slow the progress of myelin degeneration or ease the painful symptoms created by the nerve damage.

Although much work still needs to be done before this information can lead to a treatment for those with multiple sclerosis, the merit of the findings should not be discounted. Much of the research was performed on zebrafish, which have genes very similar to human genes. David Lyons, BSc, Ph.D., and principal investigator of this finding, said, "In the future, zebrafish will be used to identify new genes and drugs that can influence myelin formation and myelin repair."

Source: Czopka T, ffrench-Constant C, Lyons DA. Individual Oligodendrocytes Have Only a Few Hours in which to Generate New Myelin Sheaths In Vivo. Developmental Cell. 2013.