Stem cells in the brain may hold the key to stopping the aging process.
Scientists from the Albert Einstein College of Medicine have discovered that stem cells in the brain’s hypothalamus govern how fast aging occurs in the body, which could result in new strategies for warding off age-related diseases and extending lifespan.
The hypothalamus regulates various processes, including growth, development, reproduction and metabolism, and in 2013, researchers discovered that it also regulates aging throughout the body.
However, it wasn’t until recently that scientists were able to pinpoint a tiny population of adult neural stem cells as the exact cells that control aging.
“Our research shows that the number of hypothalamic neural stem cells naturally declines over the life of the animal and this decline accelerates aging,” senior author Dr. Dongsheng Cai, Ph.D., professor of molecular pharmacology at Einstein, said in a statement. “But we also found that the effects of this loss are not irreversible.
“By replenishing these stem cells or the molecules they produce, it’s possible to slow and even reverse various aspects of aging throughout the body,” he added.
The researchers first looked at the fate of the stem cells as healthy mice got older and found that the number of hypothalamic stem cells began to diminish when the mice reached about 10 months—several months before the usual signs of aging start appearing in mice.
The researchers next observed what happened when they selectively disrupted the hypothalamic stem cells in middle-aged mice.
“This disruption greatly accelerated aging compared with control mice and those animals with disrupted stem cells died earlier than normal,” Cai said.
The researchers injected hypothalamic stem cells into the brains of middle-aged mice whose stem cells had been destroyed, as well as into the brains of normal old mice.
The treatment slowed or reversed various measures of aging in both groups of mice.
The hypothalamic stem cells appear to exert their anti-aging effects by releasing molecules called microRNAs (miRNAs) that play key roles in regulating gene expression.
The researchers extracted the miRNA-containing exosomes from hypothalamic stem cells and injected them into the cerebrospinal fluid of middle-aged mice whose hypothalamic stem cells had been destroyed, as well as normal middle-aged mice.
After assessing changes in the animals’ muscle endurance, coordination, social behavior and cognitive ability, the researchers discovered the treatment significantly slowed aging in both groups of mice.
The next step for the research team will be to identify the particular populations of microRNAs and discover other possible factors secreted by the stem cells that are responsible for the anti-aging effects.
