Tuesday, April 24, 2007

Myelin disorders underlie schizophrenia?

White Matter Matters in Schizophrenia: Scientific American

Scientists have suspected for more than two decades that schizophrenia is linked to defects in the brain's white matter. They could not tell, however, whether changes in the information-transmitting region of the brain detected by brain scans or autopsies were the cause or the symptoms of the illness.

A new study not only clarifies the association but also links it to genes previously tied to the debilitating mental disorder and chemical changes believed to occur in the schizophrenic brain. "[The report] provides evidence that alterations in myelin [the lipid layers that sheath and insulate nerve fibers and are the main constituent of white matter] can cause defects in neurons and the central nervous system in general that are related to neuropsychiatric disease," says the study's senior author Gabriel Corfas, a professor of neurology at Harvard Medical School's Children's Hospital Boston.

Corfas's team studied mice in which they blocked the erbB4 receptor, in oligodendrocytes, which make up the myelin sheath over a neuron's communication hub. The erbB4 receptors receive a growth factor called neuregulin 1, which is necessary for proper brain development. Genes expressed in oligodendrocytes—such as the one that codes for neuregulin 1—have previously been linked to schizophrenia, bipolar disorder, depression and obsessive-compulsive disorder....

...Corfas says that the new findings indicate that screening children with noticeable cognitive and social defects for increased white matter or changes in its organization could lead to earlier diagnosis of schizophrenia. In addition, he says the results indicate that therapies designed to treat other white matter disorders such as multiple sclerosis could be useful in treating schizophrenia and other neuropsychiatric disorders.
Since there are animal models for schizophrenia I'm sure the researchers have already tested drugs developed to enhance myelin production and preservation. Those papers should be out shortly ...

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