School of Medicine

Life span increases in mice when specific brain cells are activated

A new study from Washington University School of Medicine in St. Louis has identified a key feedback loop between the brain and the fat tissue that governs aging in mice. Key neurons (shown in green) in the dorsomedial hypothalamus of the brain activate fat tissue to produce cellular fuel. When these specific neurons are activated in older mice, they live longer than control mice. (Image: Kyohei Tokizane)

In recent years, research has begun to reveal that the lines of communication between the body’s organs are key regulators of aging. When these lines are open, the body’s organs and systems work well together. But with age, communication lines deteriorate, and organs don’t get the molecular and electrical messages they need to function properly.

A new study from Washington University School of Medicine in St. Louis identifies, in mice, a critical communication pathway connecting the brain and the body’s fat tissue in a feedback loop that appears central to energy production throughout the body. The research suggests that the gradual deterioration of this feedback loop contributes to the increasing health problems that are typical of natural aging.

The study — published Jan. 8 in the journal Cell Metabolism — has implications for developing future interventions that could maintain the feedback loop longer and slow the effects of advancing age.

The researchers identified a specific set of neurons in the brain’s hypothalamus that, when active, sends signals to the body’s fat tissue to release energy. Using genetic and molecular methods, the researchers studied mice that were programmed to have this communication pathway constantly open after they reached a certain age. The scientists found that these mice were more physically active, showed signs of delayed aging, and lived longer than mice in which this same communication pathway gradually slowed down as part of normal aging.

“We demonstrated a way to delay aging and extend healthy life spans in mice by manipulating an important part of the brain,” said senior author Shin-ichiro Imai, MD, PhD, the Theodore and Bertha Bryan Distinguished Professor in Environmental Medicine and a professor in the Department of Developmental Biology at Washington University. “Showing this effect in a mammal is an important contribution to the field; past work demonstrating an extension of life span in this way has been conducted in less complex organisms, such as worms and fruit flies.”

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