Young blood: The elixir of youth?

Vampires got something right. According to new research, the blood from younger individuals may act like an elixir of youth. Young blood gave a lift to old brains and bodies — in mice, at least. Three new studies suggest compounds in the blood from young mice improve an older animal’s ability to learn, remember and build new muscle.

People have long searched for a simple way to keep old minds sharp. “Maybe they were just looking too far,” Tony Wyss-Coray told Science News. A neuroscientist at the Stanford University School of Medicine in Palo Alto, Calif, Wyss-Coray worked on one of the new blood studies. His team published its findings May 4 in Nature Medicine.

Two others studies published that same day, but in the journal Science, report similar results. All found that old mice get better at learning and remembering when they have young blood circulating in their brains.

The Science studies linked those mental and health benefits to one particular ingredient found in the blood of young mice.

Young blood confers benefits to the heart, liver and pancreas, earlier studies showed. The new ones found that an elderly mouse brain also can improve and become sharper through this simple treatment. That suggests the mental problems that many people experience when they grow older may be preventable, Lee Rubin told Science News. He’s a neuroscientist at Harvard University in Cambridge, Mass. He also worked on one of the studies just reported in Science.

How young blood may help

The experiments carried out by Wyss-Coray and his colleagues were simple. They connected blood vessels from old mice to young mice and let the blood mix. The blended blood flowed through both animals. In 2011, these researchers reported that this mixing harmed the brains of young mice getting the geezer’s blood. But the researchers now find that the same is not when the treatment is reversed. Old animals benefitted from mixing young blood into their veins.

For a mouse, “elderly” means 18 months old. That’s equivalent to a person between 55 and 70 years old. The young mice were only three months old, which corresponds to a human that’s 20 to 30 years old.

The function of nerve cells, or neurons, also improved in the old mice receiving the mixed blood. Neurons are brain cells that communicate with each other. The neurons of old mice pumping young blood appeared to grow new places where they could connect with other neurons. This growth of new connection spots is something that typically occurs in young brains. More connections should help a brain work better.

The researchers also treated old mice with 8 injections of blood plasma taken from either young mice or other geezers. (Plasma is the liquid part of blood and often looks yellowish in color.) The injections were delivered over 24 days. Afterward, the researchers tested each mouse’s ability to learn and remember new things. Old mice getting plasma from young animals performed better than those receiving plasma from other elderly mice.

But don’t worry: Grandparents won’t start poaching blood from their grandkids. The mouse findings may not hold up in people. And if they do, scientists will search for the key ingredients in blood that confer benefits. Then they can develop new treatments based only on what they learn about those ingredients.

One of those blood ingredients that shows promise is called GDF11. That stands for growth differentiation factor 11. The amount of this protein in the body falls with age. One of the new Science papers injected that protein into older mice. And it helped turn back the clock on aging. GDF11 helped these elderly mice retain muscle and strength, compared with animals who did not get the protein treatment.

The second Science study showed that GDF11 can help an elderly mouse brain grow new blood vessels and neurons. Rubin was an author of that second study. He suspects young blood’s benefits may last several weeks. “Maybe you wouldn’t have to be a Dracula feeding on fresh blood every day,” he quips.

The new studies are interesting, but only look at half of the situation, Dobri Kiprov told Science News. He studies the immune system at California Pacific Medical Center in San Francisco. The new studies “concentrate on what’s being enhanced,” he said. But just as important, he says, will be learning whether there is any harm if the treatment dilutes potentially good compounds in old animal’s blood.

Power Words

compound     A compound is a substance formed from two or more chemical elements united in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H₂O.

differentiation    The maturation of a cell or organism from a simpler form to a more complex form. Differentiation occurs as a few fertilized cells develop into an embryo acquire the specialized organs that will be needed later in life. Even cells can differentiate from a stem cell into the various specialized cells needed to later perform particular functions.

immune system  The collection of cells and their responses that help the body fight off infection.

liver   An organ of the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, breakdown harmful substances for excretion by the body, and secrete bile, a greenish fluid released into the gut, where it helps digest fats and neutralize acids.

neuron or nerve cell  Any of the impulse-conducting cells that make up the brain, spinal column and nervous system. These specialized cells transmit information to other neurons in the form of electrical signals.

neuroscience    Science that deals with the structure or function of the brain and other parts of the nervous system. Researchers in this field are known as neuroscientists.

pancreas     A gland found in animals with backbones that secretes the hormone insulin and enzymes that help breakdown foods in the gut.

plasma   The colorless fluid part of blood.

proteins   Compounds made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. The hemoglobin in blood and the antibodies that attempt to fight infections are among the better known, stand-alone proteins.