Tuesday, August 15, 2017

On July 26, 2017 in the journal Nature, researchers at Albert Einstein College of Medicine revealed a role for stem cells in the brain’s hypothalamus (a gland that regulates growth, reproduction and other processes) in regulating the rate of 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," reported senior author Dongsheng Cai, MD, PhD. "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."

Acting on the previous finding of Dr Cai and his associates that many aspects of aging throughout the body are regulated by the hypothalamus, which was reported in the May 9, 2013 issue of Nature, researchers involved in the current investigation discovered that the number of adult neural stem cells in the hypothalamus glands of mice began to decrease several months before signs of aging begin to appear. "By old age--about two years of age in mice -- most of those cells were gone," Dr Cai stated.

The team observed that the speed of aging was increased in middle-aged mice following the destruction of their hypothalamic stem cells via injection of the animals with a virus. "This disruption greatly accelerated aging compared with control mice, and those animals with disrupted stem cells died earlier than normal," Dr Cai observed.

Injecting hypothalamic stem cells into the brains of middle-aged mice resulted in retardation of measures of aging and longer life. The hypothalamic stem cells appeared to exert their effects by releasing microRNAs (which play a role in regulating gene expression) packaged in exosomes into the animals’ cerebrospinal fluid. By injecting these exosomes into the cerebrospinal fluid of middle-aged mice, aspects of aging were slowed.

“Aging speed is substantially controlled by hypothalamic stem cells, partially through the release of exosomal microRNAs,” the authors conclude.

“It's an interesting paper,” commented aging expert Leonard Guarente, who is a molecular biologist at the Massachusetts Institute of Technology in Cambridge. He predicted that the findings could lead to ways of developing antiaging therapies in humans.