A hormone with antidiabetic properties also reduces depression symptoms in mice, according to new research from the School of Medicine at the University of Texas Health Science Center.
The findings offers a new target for treating depression, especially in people who have Type 2 diabetes or are at risk for developing it, suggested the study’s senior author, Xin-Yun Lu, Ph.D., associate professor of pharmacology and psychiatry.
All types of current antidepressants, including tricyclics and selective serotonin reuptake inhibitors, increase the risk for type 2 diabetes, she noted.
The hormone, called adiponectin, is secreted by adipose tissue and sensitizes the body to the action of insulin, a hormone that lowers blood sugar.
In the study, mice were exposed to 14 days of repeated social defeat stress. Each male mouse was introduced to the home cage of an unfamiliar, aggressive resident mouse for 10 minutes and physically defeated.
After the defeat, the resident mouse and the intruder mouse were each housed in half of the cage separated by a plastic divider that allowed visual, olfactory and auditory contact for the remainder of the 24-hour period.
Mice were exposed to a new resident mouse cage and subjected to social defeat each day. Plasma adiponectin concentrations were determined after the last social defeat session.
Defeated mice displayed lower plasma adiponectin levels, the researcher reports.
When adiponectin concentrations were reduced by deleting one allele of the adiponectin gene or by a neutralizing antibody, mice were more susceptible to stress-induced social withdrawal, anhedonia (lost capacity to experience pleasure), and learned helplessness, the researcher continued.
Mice that were fed a high-fat diet (60 percent calories from fat) for 16 weeks developed obesity and Type 2 diabetes. Administration of adiponectin to these mice, as well as mice of normal weight, produced antidepressant-like effects, according to the researchers.
“These findings suggest a critical role of adiponectin in the development of depressive-like behaviors and may lead to an innovative therapeutic approach to fight depression,” Lu said.
This would be a boon for thousands of people, she said.
“So far, only about half of the patients suffering from major depressive disorders are treated to the point of remission with antidepressant drugs,” she said.
“The prevalence of depression in the diabetic population is two to three times higher than in the nondiabetic population. Unfortunately, the use of current antidepressants can worsen the control of diabetic patients. Adiponectin, with its antidiabetic activity, would serve as an innovative therapeutic target for depression treatments, especially for those individuals with diabetes or prediabetes and perhaps those who fail to respond to currently available antidepressants.”
The study was published in the Proceedings of the National Academy of Sciences.