*Myelin/MS On The Rise Articles*

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Blame Myelin for Many Neuropsychiatric Disorders

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MYELIN, BRAIN, SCHIZOPHRENIA. ALZHEIMER'S

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Neurologist Bartzokis argues that the brain's miles of myelin are

a key evolutionary change that may make us vulnerable to highly

prevalent neuropsychiatric disorders. He argues that viewing the brain

as myelin-dependent may be key to developing new and novel treatments

against disease.

Newswise — What makes the human brain unique? Of the many explanations

that can be offered, one that doesn't come readily to mind is — myelin.

Conventional wisdom holds that myelin, the sheet of fat that coats a

neuron's axon — a long fiber that conducts the neuron's electrical

impulses — is akin to the wrapping around an electrical wire, protecting

and fostering efficient signaling. But the research of UCLA neurology

professor Bartzokis, M.D., has already shown that myelin problems

are implicated in diseases that afflict both young and old — from

schizophrenia to Alzheimer's.

Now, in a report published in the journal Biological Psychiatry and

available online, Bartzokis argues that the miles of myelin coating in

our brain are the key " evolutionary change that defines our uniqueness

as a species " and, further, may also be the cause of " our unique

vulnerability to highly prevalent neuropsychiatric disorders. " The paper

argues that viewing the brain as a myelin-dependent " Internet " may be

key to developing new and novel treatments against disease and aid in

assessing the efficacy of currently available treatments, including the

use of nicotine (delivered by a patch, not smoking), which may enhance

the growth and maintenance of myelin).

Myelin, argues Bartzokis, who directs the UCLA Memory Disorders and

Alzheimer's Disease Clinic, is " a recent invention of evolution.

Vertebrates have it; invertebrates don't. And humans have more than any

other species. "

Bartzokis studied the reported effects of cholinergic treatments, using

drugs that are known to improve a neuron's synaptic signaling in people

who suffer diseases like Alzheimer's. Furthermore, he notes, some

clinical and epidemiological data suggest that such treatments may

modify or even delay these diseases

Looking at such effects from a myelin-centric point of view, Bartzokis

argues that cholinergic treatments may have nonsynaptic effects as well,

perhaps by enhancing myelination and myelin repair — and the better the

myelin, the more efficient the neuron signaling and our " Internet's "

function. Specifically, such cholinergic treatments may enhance

oligodendrocytes, a type of glia cell in the brain that produces myelin

during the brain `s development and constantly maintains and repairs it

as we age.

While more work needs to be done to fully understand the role of

nonsynaptic cholinergic effects on brain development, said Bartzokis,

his hypotheses can easily be tested through in vivo imaging of the brain

to study the breakdown and growth of myelin. That will make it possible

to directly test in humans the practical utility of the myelin-centered

model of the human brain.

Ultimately, it could foster the development of novel treatments, as well

as aid in assessing the efficacy of currently available treatments.

These include the use of cholinergic treatments that include

acetylcholinesterase inhibitors (used to treat Alzheimer's) and nicotine

patches.

" Through these rather benign interventions, " Bartzokis said, " such

effects on the brain's vulnerable oligodendrocyte populations may offer

exciting opportunities for the prevention of both developmental and

degenerative brain disorders. They deserve much closer scrutiny. "

Bartzokis work was supported in part by a National Institute of Mental

Health grant, a National Institute on Aging Alzheimer's Disease Center

Grant, Research and Psychiatry Services of the Department of Veterans

Affairs and the Sidell-Kagan Foundation.

The UCLA Department of Neurology encompasses more than a dozen research,

clinical and teaching programs. These programs cover brain mapping and

neuroimaging, movement disorders, Alzheimer disease, multiple sclerosis,

neurogenetics, nerve and muscle disorders, epilepsy, neuro-oncology,

neurotology, neuropsychology, headaches and migraines,

neurorehabilitation, and neurovascular disorders. The department ranked

No. 1 in 2005 among its peers nationwide in National Institutes of

Health funding. For more information, see

http://neurology.medsch.ucla.edu/.

http://www.newswise.com/articles/view/525430/?sc=rsmn

The mystery of multiple sclerosis — and why Canadians have it most

In Depth

Health

Last Updated November 1, 2006

CBC News <http://www.cbc.ca/news/credit.html>

http://www.cbc.ca/news/background/health/ms.html

Canadian women are more than three times more likely to get multiple

sclerosis than men, according to a major study published in November

2006. Among those born in the 1930s, about two women contracted MS for

every one man, at a ratio of 1.9 to 1. For those born in the 1980s, the

incidence has grown to exceed 3.2 cases for every one case among men.

Interactive

MS rates around the world <http://www.cbc.ca/news/interactives/map-ms/>

Why the sudden increase in the neurodegenerative disease, which attacks

the brain and spinal cord, and can lead to paralysis and sometimes

blindness?

We don't know. We don't know what causes MS. We don't know what cures

MS. The whys and wherefores of this mysterious disease have bedevilled

scientists, health-care workers and victims for nearly 200 years.

Recent speculation about the cause has ranged from genetics to

environment to vitamin deficiencies to even the birth control pill.

Canada has highest rate, especially in Prairies

One thing we know for sure about MS is that Canada has the highest

incidence of the disease in the world — a whopping 240 cases among every

100,000 people, according to a study by a University of Calgary team

published in the journal Multiple Sclerosis in 2005.

Health officials consider a country to have a " high " rate if they have

more than 30 cases per 100,000.

The incidence among the provinces varies, from a high of 340 cases for

every 100,000 people in the Prairies to a low of 180 cases per 100,000

in Quebec.

But overall, it works out about 1,000 Canadians being diagnosed each

year with MS and more than 75,000 living with it. Those between ages 15

and 40 are most at risk. One out of every two Canadians know someone

with MS.

Another thing we know about MS is that people who live closest to the

equator have the lowest incidence.

However, that doesn't help explain why the disease is nearly absent

among Canada's Inuit in the High Arctic and among indigenous people in

North America and Australia, or why it is rarely found in Japan.

Study suggests MS is environment-based, preventable

The latest study on the rising incidence of women with MS was done by a

team of researchers led by Ebers, a professor of neurology at the

University of Oxford. It appears in the November 2006 issue of the

journal Lancet Neurology.

The higher incidence of MS among women may not be bad news, according to

the researchers — because it may help to shed light on what causes the

disease.

" What is going on here is something presumably that is preventable, "

said Ebers, who was the lead author of the study.

" We just need to find out what it is in the environment. Because it has

to be in the environment: your genes don't change over two generations,

three generations. "

Others blame higher estrogen levels, less sunlight

There has also been speculation that because MS is generally more

prevalent in colder climates far north of the equator and far south of

the equator, it may be due to vitamin D deficiencies.

The body produces the vitamin in response to sunlight and so vitamin D

levels fall off in colder countries and in winter because the sun's rays

aren't intense enough.

Because of the rising incidence of MS among women and because it seems

to have started in the 1960s, many others have speculated that the cause

may be connected to higher levels of the hormone estrogen due to the

introduction of the birth control pill.

But Ebers, who spent 22 years at the University of Western Ontario in

London, Ont., before going to Oxford, rejects these factors as likely

explanations.

" I think one of the things one thinks of here is either that it's going

to be something in the environment or it is going to be an environmental

interaction with genes. "