Study in humans & rats shows more physical changes in depressed brains
(September 9, 2015) Low. Down. Less than normal. That’s what the word depression means, and what people with depression often feel like. But sometimes, depression can mean too much of something – as new research shows.
The discovery, about a protein called fibroblast growth factor 9 or FGF9, goes against previous findings that depressed brains often have less of key components than non-depressed brains.
In this case, people with major depression had 32 percent more of FGF9 in a key part of their brain than people without the condition. In rats, raising FGF9 levels artificially led to depression-like behavior changes, and repeated social stress caused brain FGF9 levels to rise.
Taken together, the findings provide more evidence that depression is a physical illness. If FGF9 or its effects prove to be a good target for drugs, the finding could eventually help lead to better medications for the mental health condition that affects millions of Americans.
FGF9’s role was discovered by a team from the University of Michigan Medical School and the Pritzker Neuropsychiatric Disorders Research Consortium, who report their results today in the Proceedings of the National Academy of Sciences. They made the discoveries through years of detailed comparisons of brain tissue donated by people with and without depression, and multiple studies in rats.
The green cells show where the researchers used an injected virus to block
production of FGF9 in rat brains -- and reduce anxiety-like behavior.
Because drugs that block excess production of something in the body generally cause fewer side effects than drugs aimed at increasing something, the team says their findings could hold promise for the development of a new class of antidepressants.
“Fixing depression is not easy, because it’s a disorder at the level of the circuits that connect brain cells, and many regions of the brain are involved,” says Elyse Aurbach, the neuroscience doctoral student who is the paper’s co-first author. “Still, this is the first time FGF9 has been identified as related to depression, and found to be active in a critical area of the brain for the disorder. We and others need to study it further to determine what is going on. It’s very exciting.”