A simple vitamin has dramatically reduced neurological damage in mice suffering from a multiple sclerosis-like illness, a new study reveals.

As a result, the researchers hope that a form of vitamin B3 (niacin or nicotinamide), may help reduce long-term disability in people with multiple sclerosis.

MS is caused by the body's immune system attacking the protective myelin sheath that coats nerve cells. Without this white, fatty material, electrical signals passing to and from the brain are disrupted, and sufferers become increasingly physically disabled. There is currently no cure.

Current drugs aim to reduce destruction of myelin by suppressing patients' immune systems. However, this has a side effect of making them more prone to infection. And these drugs do nothing to conserve remaining nerves – even if they lack myelin – once the disease has progressed.

Late-stage help

In the new research, Shinjiro Kaneko at the Children's Hospital Boston in Massachusetts, US, and colleagues gave a daily dose of nicotinamide to mice that had an MS-type disease, called experimental autoimmune encephalopathy (EAE).

The vitamin protected the mice from further myelin damage and improved the function of nerve cells that had lost myelin, suggesting that it could help people in late-stage MS. The more nicotinamide they gave the mice, the greater the protective effect, the team found.

Mice receiving daily injections of nicotinamide only showed slightly reduced mobility, such as the dragging of a hind leg. In contrast, mice in the no-treatment group had severe hind-limb weakness or paralysis.

Sight saving

"That's an enormous difference," says Peter Werner at the Albert Einstein Collage of Medicine in New York, US, who was not involved with the study. "It is the difference, for example, between a mouse that can reach its food and one that can't."

"It's highly desirable to hang on to functioning nerves as long as possible, even if they're naked because they have no myelin," Werner told New Scientist. He adds that doing so could potentially delay loss of mobility or sight in a patient with MS.

When nerves lose myelin they have to work harder to send signals, and this stress appears to damage them further, Werner explains.

Widely available

Kaneko believes that nicotinamide worked in the mice because it raises the level of a key nervous system chemical called nicotinamide adenine dinucleotide (NAD), which appears to improve the energy efficiency of nerve cells. And NAD may also inactivate the immune cells that attack myelin, Kaneko suggests.

Nicotinamide is widely available in health food stores and pharmacies as a form of vitamin B3. The proven safety and availability of the compound make it an appealing candidate to treat MS, experts say, particularly since the chemical is small enough to cross the blood-brain barrier.

And unlike current multiple sclerosis (MS) drugs, nicotinamide does not appear to have unpleasant side effects.

However, Kenneth Maiese at Wayne State University School of Medicine in Detroit, Michigan, US, points out that the doses given to the mice in the study were quite high. Similar doses in humans may prove toxic, he cautions.

For this reason, experts stress that MS patients should not take vitamin B3 for their illness until clinical trials show that it has an effect in humans.

Journal reference: Journal of Neuroscience (DOI: 10.1523/jneurosci.2116-06.2006)