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A family of molecules surrounding brain cells may play a critical role in the pathology of schizophrenia, according to findings being reported by researchers at Harvard-affiliated McLean Hospital. The findings may one day lead to improved diagnosis and treatment of the psychiatric disorder.
The study, published in the Archives of General Psychiatry, found that the expression of these molecules, called chondroitin sulfate proteoglycans (CSPGs), is altered in the amygdala and the entorhinal cortex regions of brains of patients with schizophrenia. CSPGs represent one of the main components of the extracellular matrix, a molecular lattice that surrounds all cells in the brain.
Researchers at McLean studied the amygdala and entorhinal cortex in people who had suffered from schizophrenia or bipolar disorder, as well as in people not affected by psychiatric illnesses. Both these brain regions are known to play a role in schizophrenia, although the amygdala in particular has not been widely studied. The amygdala plays a key role in the processing of emotions, while the entorhinal cortex is an important memory center in the brain.
In people with schizophrenia, CSPGs were found to be overexpressed in glial cells, one type of brain cell, but decreased within the extracellular matrix in both brain regions. No such abnormalities were found in the brains of people with bipolar disorder.
“These findings are very exciting,” said Dr. Sabina Berretta, senior author and Director of the Translational Neuroscience Laboratory at McLean and an assistant professor of psychiatry at Harvard Medical School.
“They are only the beginning, but they are novel,” she said. “It is only one study, but it may potentially lead to a new, more cohesive, understanding of the pathology of this disease and could help in the future to improve treatment and diagnostic reliability for schizophrenia.”
She added: “The difference found between schizophrenia and bipolar disorder is particularly important, because these two diseases present with many similarities. Finding out how they could be different is potentially helpful.”
She noted that CSPGs are known to have several functions in both brain development and adult brain function and interact intricately with a multitude of brain cell types.
“Our findings, although preliminary, may offer a conceptual framework within which we can begin to integrate many seemingly unrelated aspects of our current understanding of cellular disturbances in schizophrenia at the genetic, molecular, cellular, developmental, and system levels,” she said.
Other researchers who participated in the study included Harry Pantazopoulos, ALM; Dr. Tsung-Ung Woo; Maribel P. Lim, BA; and Nicholas Lange, ScD.
McLean Hospital is an affiliate of Harvard Medical School and Massachusetts General Hospital, and a member of Partners HealthCare.