Brain gains seen in elderly mice injected with human umbilical cord plasma

mouse hippocampus
YOUTHFUL GLOW In the hippocampus of a 1-month-old mouse, some nerve cells (red) produce the protein TIMP2 (green), which declines with age and may help keep the brain young. Blue indicates microglial cells.

Plasma taken from human umbilical cords can rejuvenate old mice’s brains and improve their memories, a new study suggests. The results, published online April 19 in Nature, may ultimately help scientists develop ways to stave off aging.

Earlier studies have turned up youthful effects of young mice’s blood on old mice (SN: 12/27/14, p. 21). Human plasma, the new results suggest, confers similar benefits, says study coauthor Joseph Castellano, a neuroscientist at Stanford University. The study also identifies a protein that’s particularly important for the youthful effects, a detail that “adds a nice piece to the puzzle,” Castellano says.

Identifying the exact components responsible for rejuvenating effects is important, says geroscientist Matt Kaeberlein of the University of Washington in Seattle. That knowledge will bring scientists closer to understanding how old tissues can be rejuvenated. And having the precise compounds in hand means that scientists might have an easier time translating therapies to people.

Kaeberlein cautions that the benefits were in mice, not people. Still, he says, “there is good reason to be optimistic that some of these approaches will have similar effects on health span in people.”

Like people, as mice age, brain performance begins to slip. Compared with younger generations, elderly mice perform worse on some tests of learning and memory, taking longer to remember the location of an escape route out of a maze, for instance. Researchers suspect that these deficits come from age-related trouble in the hippocampus, a brain structure important for learning and memory.

Every fourth day for two weeks, Castellano and colleagues injected old mice with human…