Brain region found to control aging

For the first time, a brain region has been found that may control aging throughout the whole body, a new study reports.

A signaling pathway in the brain region known as the hypothalamus could speed up or slow down aging in mice. If it applies in humans, the discovery could open up possibilities for slowing age-related diseases and increasing life span.

"There's really not much understanding regarding the mechanism of aging," said senior author Dr. Dongsheng Cai, a molecular pharmacologist at Albert Einstein College of Medicine in New York.

The process of aging could involve chaotic, passive changes in individual tissues or organs, or it could be controlled centrally by a single organ or both, Cai told LiveScience.

The hypothalamus, an almond-size structure deep inside the brain, is known to control important functions, including growth, development, reproduction and metabolism. Now, Cai and his team have found that an immune system pathway in the hypothalamus also has a role in controlling aging. Usually, the immune system is involved in fending off infection or damage, but studies have also linked inflammatory changes with age-related conditions, including cardiovascular disease and neurodegenerative diseases. Still, these changes weren't known to actively trigger aging.

Making mice tick

In the study, Cai and his colleagues probed the hypothalamus's role in aging in mice. The team studied a protein complex called nuclear factor kappa-light-chain-enhancer of activated B cells (NF-B), which plays a central role in inflammatory processes.

The researchers showed that activating the NF-B pathway in the mouse hypothalamus sped up aging, demonstrated by decreased muscle strength and size, skin thickness and learning ability. The activation led to aging throughout the body that shortened the life span of the mice.

In contrast, when the researchers blocked the NF-B pathway, the mice aged more slowly and lived about 20 percent longer than mice that didn't receive the treatment.

Furthermore, activating the NF-B pathway led to a drop in the levels of gonadotropin-releasing hormone (GnRH), a neuron-generating chemical, and a subsequent decrease in the development of new neurons. GnRH is known to regulate reproductive processes, but seems also to be necessary for maintaining youthfulness, Cai said.

When the researchers injected GnRH into the hypothalamuses of mice, it promoted neuron generation and decelerated aging. The team gave daily GnRH injections to old mice over an extended period, finding that the treatment slowed cognitive decline due to aging.

Putting the brakes on aging

GnRH treatment represents a potential means of slowing the progress of aging or age-related diseases, the researchers say. Interfering with the immune response in the hypothalamus could also be a promising approach, Cai said, though he added that the GnRH treatment might be more practical given current technology.