The Role of the Blood-Brain Barrier
And just when you think you've finally grasped it all, the blood-brain barrier comes into play. In simple terms, the blood-brain barrier is like a shield that exists to prevent chemicals and cells in the bloodstream from entering the CNS, while allowing the good stuff to pass through. Magnetic resonance imaging (MRI) shows that when a person with MS is having a relapse, the blood-brain barrier has broken down in the brain or spinal cord. This allows immune cells to cross over and attack the myelin.
Alert
Most people experience their first symptoms of MS between the ages of twenty and forty. Although scientists have documented cases of MS in young children and elderly adults, symptoms rarely begin before age fifteen or after age sixty. The average age of diagnosis is between twenty-nine and thirty-three years of age.
A key player in MS is a white blood cell in the immune system called a T cell. Scientists have learned that when specific T cells become activated, they leave the bloodstream and cross the blood-brain barrier to damage myelin.
Putting It All Together
Although MS is referred to as a neurological disorder, the problem seems to originate with the immune system. Research has shown that some sort of malfunction in the immune system interferes with the functioning of the nervous system. The process seems to follow these steps:
A faulty immune system loses the ability to distinguish the good cells from the bad cells.
A breakdown in the blood-brain barrier allows immune cells to travel into the CNS to attack the myelin and axons.
Toxic substances are released into the CNS, causing inflammation and resulting in the breakdown of myelin (in a process called demyelination) and axons.
Scar tissue forms where nervous system damage has occurred.
The inflammation, demyelination, and broken axons cause the nerve impulses to be slowed down in the transmission process, resulting in neurological symptoms.
The body tries to heal some of the damage caused by this process by naturally reducing inflammation and doing its best to regenerate myelin.
A useful way to picture the process of MS is to imagine a lamp cord. The electrical wire within the lamp cord is protected by a plastic coating, just as myelin coats and protects the nerves. Now, imagine that some kind of incident occurs that damages the cord in several small places. When you turn on the lamp, the electrical current may be disrupted, resulting in a faulty lamp. This is similar to what happens during an attack (or an exacerbation). Perhaps you grab a roll of electrical tape and try to patch up areas of damage on the cord, which is similar to what happens in remyelination. Now imagine further that the cord is somehow severed. In MS, broken or severed axons are no longer able to transmit a signal.
Essential
Repairing damaged myelin is the focus of the Myelin Repair Foundation, an organization whose aim is to accelerate research for myelin repair. Repairing the myelin damaged by MS may improve signal transmission in the central nervous system and reduce the symptoms of the disease. For more information visit
