Year in review: Young blood aids old brains

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Ingredients in young blood can rejuvenate old mice’s bodies and brains. A group of papers published in 2014 detail how youthful plasma can improve some signs of deterioration (SN: 5/31/14, p. 8).

The findings evoke thoughts of eternally young and bloodthirsty vampires, but in reality, the results are pointing to new treatments that may stave off the ravages of aging. Already, scientists have begun a small clinical trial to study whether plasma from young donors can improve symptoms in people with Alzheimer’s disease.

Brain cells in old mice whose circulatory systems were surgically linked to young mice showed signs of improvement:  gene behaviors changed and neurons sprouted more connecting points, Tony Wyss-Coray of Stanford University School of Medicine and colleagues found. Another study discovered that young blood increases the birthrate of nerve cells in a part of older brains, leading to better smelling abilities, and remodels blood vessels in a way that boosts blood flow.

Such improvements could be achieved even without drastic surgery: Old mice that received a series of injections of young plasma appeared to have stronger memories than did old mice that received old plasma. The benefits of young plasma disappeared when the plasma was heated before injection, suggesting that certain heat-sensitive compounds in the plasma were behind the improvements.

Young blood may be packed with substances that keep the body and brain strong. One candidate molecule, called GDF11, popped up in two studies as a potential do-gooder. On its own, GDF11 benefited both the brains and muscles of mice.

Drugs designed to mimic GDF11 or other beneficial molecules in young blood may prevent some of the negative effects of aging. In the meantime, some scientists are hedging their bets by using plasma from young donors in studies. A clinical trial, led by Stanford University scientists and the biomedical company Alkahest, cofounded by Wyss-Coray, involves injecting a unit of plasma from men age 30 or younger once a week into 18 elderly people with Alzheimer’s. The trial began in September, and scientists plan to have results in about a year.