The study, published in Nature, comes out of the same lab that in 2014 gave us the story I'll paraphrase as “young blood recharges old mice's brains,” which not only received wall-to-wall press coverage but generated its own New Yorker cartoon. In that set of experiments, old mice who got infusions of plasma (the cell-free extract of blood) from young adult mice did better on tests of memory and learning. They also showed numerous biochemical and physiological signs of rejuvenation in their hippocampus, a brain structure that's critical for converting experiences into long-term memories.
The new study goes several steps further: The researchers used human blood. The blood that worked best was the "youngest blood of all"-- it came from (human) umbilical cords. And the scientists isolated a specific protein in cord blood that pretty much seemed to get the job done all by itself.
The hippocampus is essential for helping you remember spatial information (for instance, how to find your way back to the car you parked in a multilevel structure several hours ago) and information about autobiographical events (what you ate for breakfast). Unfortunately, in both mice and humans, the hippocampus also seems particularly vulnerable to normal aging. With advancing age, it degenerates, loses nerve cells and shrinks. Our capacity to learn and remember falters in lockstep with that physiological deterioration.
A classic laboratory test of a mouse's spatial memory is called the Barnes maze. From my news release on the study:
[The Barnes maze] employs a table, about 4 feet in diameter and 1.3 feet high, that is brightly lit and open to the surrounding environment -- two factors that make mice feel insecure. The table is also full of holes, one of which is attached to a tube in which a scared mouse can find darkness and safety. The other holes offer only a drop to the floor... Which hole has a burrowing tube attached to it can be changed from one session to the next. Visual cues to its location can also be transferred to help guide the mouse to the escape hole, memory permitting.
Older mice ordinarily bomb the Barnes maze. But their performance perked right up after they got shots of plasma derived from human umbilical cord blood, obtained from consenting moms undergoing caesarian sections. Topping it all off, a single protein that's abundant in human cord blood but whose levels decline with advancing age (it goes by the acronym TIMP2) produced the same results when injected by itself into the animals.
Rhetorical question: If something from human blood makes elderly mice better at remembering where they parked the cheese, do you think the same something might have some beneficial effects on a person’s memory? Just asking.
The researchers hope their findings could lead to new treatments for age-associated declines in mental ability.
Previously: The rechargeable brain: Blood plasma from young mice improves old mice's memory and learning, Old blood + young brain = old brain and Old blood makes young brains act older, and vice versa
Photo of Tony Wyss-Coray by Norbert von der Groeben