Kaminsky says the genes in question may have something to do with the creation of new cells in the hippocampus and the ability of the brain to reorganize and adapt in the face of new environments two elements important in mood. In some ways, he says, estrogen can behave like an antidepressant, so that when inhibited, it adversely affects mood.
The researchers later confirmed their findings in humans by looking for epigenetic changes to thousands of genes in blood samples from 52 pregnant women with mood disorders. Jennifer L. Payne, M.D., director of the Johns Hopkins Women's Mood Disorders Center, collected the blood samples. The women were followed both during and after pregnancy to see who developed postpartum depression.
The researchers noticed that women who developed postpartum depression exhibited stronger epigenetic changes in those genes that are most responsive to estrogen, suggesting that these women are more sensitive to the hormone's effects. Specifically, two genes were most highly correlated with the development of postpartum depression. TTC9B and HP1BP3 predicted with 85 percent certainty which women became ill.
"We were pretty surprised by how well the genes were correlated with postpartum depression," Kaminsky says. "With more research, this could prove to be a powerful tool."
Kaminsky says the next step in research would be to collect blood samples from a larger group of pregnant women and follow them for a longer period of time. He also says it would be useful to examine whether the same epigenetic changes are present in the offspring of women who develop postpartum depression.
Evidence suggests that early identification and treatment of postpartum depression can limit or prevent debilitating effects. Alerting women to the condition's risk factors as well as determining whether they have a previous history of the disorder, other mental illness and unusual stres
|Contact: Stephanie Desmon|
Johns Hopkins Medicine