UBC Reports | Vol. 49 | No. 10 | Oct.
2, 2003
Brain cell insulation may be the key
By Hilary Thomson
A UBC researcher has made a breakthrough that promises new
treatment for schizophrenia in the treatment of
schizophrenia patients.
Psychiatry Prof. Bill Honer has discovered that schizophrenia
patients show a significant loss of myelin — the material
that surrounds and insulates brain cells and helps transmit
messages within the brain — compared to people without the
disease. Using magnetic resonance imaging (MRI), he found
there was particular loss of myelin in the frontal lobes of
the brain that are the site of decision-making and memory
functions. He believes the myelin abnormality could be a contributing
factor in patients’ slow recovery from the illness.
“These findings represent another window into the mechanism
of schizophrenia and open up a whole new area for developing
treatments,” says Honer, who holds the Jack Bell Chair
in Schizophrenia and is a member of the Vancouver Coastal
Health Research Institute. “Our current treatments can
regulate the disease to some extent, but even with medication
many patients are still impaired.”
This is the first study ever to focus specifically on myelin
loss in living patients. Previous research has examined the
general condition of white matter, the material in the central
core of the brain that includes myelin and other components.
Honer’s work confirms in living patients what other researchers
have recently discovered in gene studies using post-mortem
samples.
The findings of the 1997-2001 study were reported recently
in Molecular Psychiatry, a journal of the Nature Publishing
Group.
Using MRI technology developed by UBC multiple sclerosis
(MS) researchers, Honer and his research team looked at MRI
scans of 30 patients with schizophrenia and compared them
to a control group. The patients, who agreed to participate
in the study, were being treated by research team member Dr.
Sean Flynn at Riverview Hospital, a site of the Provincial
Health Services Authority.
The scans showed a 12 per cent loss of myelin, a biological
effect that may be compared to the appearance of frayed insulation
around electrical wiring. Researchers don’t know the
cause of the abnormalities, however, they do know that they
can impair synchronization of signals between brain cells,
which could give rise to schizophrenia symptoms such as hallucinations,
delusions and distorted thinking.
In a second part of the study, Honer looked at 13 post-mortem
samples of brain tissue collected from hospitals around the
world. He analyzed two proteins found in the cells that make
myelin. One of these proteins was 33 per cent lower in brain
samples from patients who had schizophrenia. The information
complements the MRI findings and will further help scientists
understand how brain cell communication is impaired among
schizophrenia patients.
Honer cautions that abnormal myelin does not necessarily
mean a patient will develop schizophrenia. Scientists haven’t
yet found a way to reverse myelin degradation, but drugs in
development to treat MS patients — who also suffer myelin
loss — may improve the condition in patients with schizophrenia.
Affecting an estimated one person in 100, schizophrenia most
often develops in individuals aged 16-30 years. The mechanism
of illness remains unclear. The disease affects women and
men with equal frequency and often appears earlier in men.
A biological disorder of the brain, schizophrenia is treated
with a number of medications that help to balance complicated
interrelated chemical systems of the brain. The medications
can have serious side effects, however, ranging from drowsiness
to loss of white blood cells. About 10 per cent of individuals
with schizophrenia commit suicide.
“Schizophrenia is a tragic illness for both patients
and their families and treatment hasn’t changed much
in 50 years,” says Honer. “These new avenues of
research reinforce that this is a biological disorder and
gives further hope for better treatments.”
Next steps in Honer’s research program include studying
how nerve cells communicate with cells that make myelin, looking
at genetic variations in myelin and determining exactly how
myelin loss affects function.
