Scientists found that the fibroblast growth factor system, which is a family of proteins involved in the growth, development and maintenance of nerve cells, had an overall decrease in levels in patients who had major depressive disorder. Proteins are the products of gene expression.
"This study is the first to implicate this particular family of gene products in major depression," said Edward G. Jones, professor of psychiatry and director of the Center for Neuroscience at UC Davis and a principal investigator of the study. "The fibroblast growth factor system is now important to consider when looking for causes of mood disorders."
Growth factors bind to receptors on the surface of cells, setting in motion a variety of biological activities. The fibroblast growth factors are critical during brain development and also help maintain the central nervous system in adulthood.
The scientists applied microarray technology, a powerful new tool used to create gene expression profiles, to biological samples from specific areas of the brain at autopsy. Recently deceased people who had suffered from major depressive disorder or bipolar disorder were compared to controls who had no mood disorder. Those with major depressive disorder had different amounts of fibroblast growth factors than the controls. Those with bipolar disorder did not show these differences.
Interestingly, subjects with major depression who had been treated with selective serotonin reuptake inhibitors (SSRIs), a common medication for depression, showed smaller changes in the fibroblast growth fact